SUSANNE CHRISTINA LEWIS [2026] SASC 48

Applicant: SUSANNE CHRISTINA LEWIS Counsel: MR M O'CONNOR - Solicitor: DW FOX TUCKER First and Second Respondent: DIANA MAYFIELD (AS EXECUTOR AND TRUSTEE OF THE ESTATE OF BRENTON JOHN MAYFIELD) AND ARISTOS NOMINEES PTY LTD (AS TRUSTEE FOR THE BRENTON JOHN MAYFIELD FAMILY TRUST) Counsel: MR M HOFFMAN KC - Solicitor: ILLES SELLY LAWYERS First Third Party: SUSANNE CHRISTINA LEWIS (AS EXECUTOR OF THE ESTATE OF GRANT ROBERT MAYFIELD) Counsel: MR M O’CONNOR - Solicitor: DW FOX TUCKER Second, Third, Fourth and Fifth Third Parties: JULIA JAYNE BELL AND ROBINA JUSTINE TRIGGS (AS EXECUTORS OF THE ESTATE OF GRANT ROBERT MAYFIELD), JULIA JAYNE BELL AND ROBINA JUSTINE TRIGGS Counsel: MR E GUTHRIE - Solicitor: RANDLE & TAYLOR Hearing Date/s: 16/03/2026 File No/s: CIV-24-004361 B SUPREME COURT OF SOUTH AUSTRALIA (Civil: Application) DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment. The onus remains on any person using material in the judgment to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court in which it was generated. LEWIS v MAYFIELD & ORS [2026] SASC 48 Reasons for Decision of the Honourable Justice McIntyre 17 April 2026 PROCEDURE - CIVIL PROCEEDINGS IN STATE AND TERRITORY COURTS - MOTIONS, INTERLOCUTORY APPLICATIONS AND OTHER PRE-TRIAL MATTERS PROCEDURE - CIVIL PROCEEDINGS IN STATE AND TERRITORY COURTS - PROCEDURAL ASPECTS OF EVIDENCE - SUBPOENAS AND NOTICE TO PRODUCE AT HEARING - SETTING ASIDE OR OTHER RELIEF The respondents seek leave to uplift and inspect material produced under subpoena by Ochre Health Pty Ltd (‘Ochre’). Leave to issue the subpoena was granted on 5 February 2026. The respondent contends that the medical records, produced under the subpoena, are relevant to allegations of unconscionable conduct and the question of special disadvantage as pleaded in the Statement of Claim. The applicant opposes the application, contending that the subpoena is overly broad, being used impermissibly as a substitute for discovery and that the subpoena was issued for an improper purpose. It is said that the subpoena constitutes a fishing expedition, as the medical records would not materially assist the case of either party. Held: 1. The respondent is granted leave to uplift, inspect and copy the materials produced under the subpoena issued to Ochre Health Pty Ltd. -- 1 of 7 -- Uniform Civil Rules 2020 (SA) r 156.2, referred to. Secretary of the Department of Planning, Industry and Environment v Blacktown City Council [2021] NSWCA 145; Stubbings v James 2 Pty Ltd (2022) 276 CLR 1; Commercial Bank of Australia Ltd v Amadio (1983) 151 CLR 447; Australian Competition & Consumer Commission v Radio Rentals Ltd [2005] FCA 1133, considered. -- 2 of 7 -- LEWIS v MAYFIELD & ORS [2026] SASC 48 Civil: Application McIntyre J. 1 The respondents sought leave pursuant to r 156.2 of the Uniform Civil Rules 2020 (SA) (‘UCR’) to issue a subpoena to Ochre Health Pty Ltd (‘Ochre’) by interlocutory application filed on 14 January 2026. Leave was granted by order made on 5 February 2026. Ochre has since produced documents in response, comprising the complete medical file and records of the late Grant Mayfield. 2 The respondents now seek leave to uplift and inspect the documents produced by Ochre. The applicant opposes that application on three grounds: that the subpoena is overly broad; that it is being used impermissibly as a substitute for discovery; and that it was issued for an improper purpose. 3 Although the applicant’s submissions were directed to opposing leave to issue the subpoena, leave was not opposed at the time it was granted on the basis that any dispute would be confined to inspection of the produced documents. In those circumstances, the respondent contended that I ought to decline to set aside the subpoena and proceed to determine the respondents’ entitlement to inspect the material produced. I accept that this is a proper basis upon which to proceed in the circumstances, however, for the reasons that follow I would, in any event, have declined to set aside the subpoena. Background 4 The background to the proceedings is set out in the affidavit of Nicholas James Iles sworn on 21 March 2025. In summary, the proceedings concern the FR and JW Mayfield Family Trust (‘the Trust’). The applicant is Grant Mayfield’s eldest daughter. The claims include allegations that Brenton Mayfield, Grant Mayfield’s deceased brother, breached his duties as trustee; that Brenton Mayfield committed fraudulent breaches of his duties as a trustee; and that the second respondent was a knowing recipient of trust property transferred by Brenton Mayfield in breach of trust. 5 The Statement of Claim pleads that Grant Mayfield was in a position of special disadvantage, relying on matters pleaded at paragraphs 45 to 48 of the Statement of Claim.1 Those matters include his autism spectrum disorder (‘ASD’), his educational and employment background, his limited financial and legal knowledge relative to Brenton Mayfield, the nature of their relationship and Brenton Mayfield’s position of influence and power since 1989. 1 FDN 3 (Revision 1). -- 3 of 7 -- [2026] SASC 48 McIntyre J 2 Applicant’s contentions Scope of the subpoena 6 The applicant submits that the subpoena is too broad and seeks access to irrelevant and confidential medical material. Dr Michael Simpson, now deceased, was Grant Mayfield’s general practitioner for approximately 19 years until Grant Mayfield’s death on 3 August 2023. It is submitted that Grant Mayfield was first diagnosed as meeting the DSM-5 criteria for ASD on 5 February 2019 and that the only potentially relevant material in the medical file concerns references to that diagnosis between 5 February 2019 and 3 August 2023. Substitute for discovery 7 The applicant further contends that the subpoena is being used as an impermissible substitute for discovery, noting that the applicant holds the medical file and will disclose any relevant documents. Improper purpose 8 The applicant contends that the subpoena has been issued for an improper purpose in that it constitutes an impermissible fishing expedition extending beyond the issues in the proceedings, with no apparent basis to conclude that the documents would materially assist the case of any party for the reasons set out in the applicant’s written submissions.2 9 In summary, the applicant contends that paragraphs 45.2 and 45.3 of the Defence deny that Grant Mayfield had ASD, but that if he had:3 (a) any such diagnosis was not apparent; (b) further and [in] any event, it was not a condition which was known to Brent; (c) it was not a condition that Brent took advantage of unconscientious[ly] or otherwise; (d) any such condition did not prevent or adversely affect Grant in his business, professional and personal life in which he enjoyed great success. 10 The applicant contends that the Ochre file is not relevant to those allegations in the Defence. It is further said that the allegation at 45.3.1 of the Defence, that an ASD diagnosis was not apparent, is a confusing allegation, as it lacks an object; that being who the diagnosis was not apparent to. The applicant says that the medical records would not assist in proving that the diagnosis was not apparent and, further, it is said that the diagnosis was apparent to Dr Glen Craig, the psychiatrist who provided a report dated 5 February 2019, and Dr Robyn Young, the psychologist who provided a report dated 24 January 2022. 2 FDN 61 at [71]–[77]. 3 FDN 6. -- 4 of 7 -- [2026] SASC 48 McIntyre J 3 Respondent’s contentions 11 Grant Mayfield, Brent Mayfield and the general practitioner, Dr Simpson, are all deceased. In those circumstances the respondent contends that the main repository of Grant Mayfield’s medical history is the Ochre file. The respondent says that it is “on the cards” that, on the face of the pleadings and in circumstances where the relevant people are unable to give evidence, the medical records will assist the Court to determine the issues in dispute. 12 The respondent says that the applicant’s case is founded on an allegation of unconscionable conduct or, otherwise, fraud perpetrated by Brent Mayfield upon Grant Mayfield by reason of Grant Mayfield’s special disadvantage as pleaded in paragraphs 45 to 48 of the Statement of Claim.4 The matters pleaded include a list of “relevant difficulties”. These, it is said, are not founded solely upon the diagnosis of ASD in February 2019 but upon decades of “difficulties”. The respondents join issue with those allegations in the Defence. The context of what was or was not apparent and what was or was not indicia of the alleged special disadvantage is said to be clearly relevant to resolution of this matter. The Ochre file is, in the circumstances, said to be the best evidence of Grant 0Mayfield’s medical history. 13 Further it is said that the confidentiality or privacy issue raised by the applicant is misconceived because the medical condition and general circumstances of the late Grant Mayfield are squarely in issue on the pleadings. Consideration 14 It is necessary that the documents sought have an apparent relevance to the issues in dispute and that there is a reasonable possibility that they will materially assist the respondent’s case, in other words, that the subpoena has been issued for a legitimate forensic purpose. As observed by Brereton JA in Secretary of the Department of Planning, Industry and Environment v Blacktown City Council:5 I agree with Bell P, for the reasons given by his Honour, that an issuing party is not required to show that it is “likely” (or “on the cards”) that the documents sought will materially assist its case, as distinct from that it is “likely” (or “on the cards”) that they will add, in some way or another, to the relevant evidence in the case, and that the essential question is whether the documents called for are apparently relevant, or capable of providing a legitimate basis for cross‐examination, in which case there is a legitimate forensic purpose for the issue of the subpoena. In my view, at least in civil proceedings and in the absence of any question of public interest immunity, no more is required to support the issue of a subpoena for production than that there is a reasonable basis for supposing that the material called for will likely add, in the end, in some way or another, to the relevant evidence in the case. This reflects the notions that the documents relate to, throw light on, or are sufficiently relevant to the dispute; that they “appear relevant in the sense that they relate to the subject matter of the proceedings”; or that they could possibly throw light on the issues in the case. Moreover, documents will add “in some way” to the relevant evidence 4 FDN 3 (Revision 1). 5 [2021] NSWCA 145 at [89]; see also Bell P at [65], [80] and McCallum JA at [98]. -- 5 of 7 -- [2026] SASC 48 McIntyre J 4 in the case if they are capable of assisting in cross‐examination, or go to credit, and notwithstanding that they are inadmissible according to the rules of evidence. [Citations omitted] 15 Accordingly, the bar is not high albeit the documents sought must relate to the issues in the case and the request cannot be too broad. 16 The applicant contends that the request is too broad on the basis that the diagnosis of ASD was only made on 5 February 2019 and the medical notes cover a 19 year period dating back to about 2004. I reject the applicant’s submission insofar as it relates to the confidentiality of such records. If the late Grant Mayfield’s medical condition is relevant to the issues raised by the pleadings, then confidentiality of his medical records is no bar to production and inspection. 17 The pleadings raise issues relevant to the claim of special disadvantage arising from undiagnosed ASD and other issues. The report of Dr Craig,6 in which the diagnosis was outlined, indicates that ASD is not a disorder of gradual onset; it is a lifelong condition. The transactions that are the subject of the proceedings date back to the 1980’s. The applicant’s pleaded case is that Grant Mayfield was at all material times subject to a special disadvantage, that Brenton Mayfield was aware of at least some, or all, of the matters that related to this special disadvantage7 and that he unconscionably took advantage of that to Grant Mayfield’s detriment. 18 The High Court has recently considered unconscionable conduct in Stubbings v James 2 Pty Ltd (‘Stubbings’).8 Chief Justice Kiefel, Keane and Gleeson JJ referred to the seminal case Commercial Bank of Australia Ltd v Amadio (‘Amadio’)9 in stating:10 …unconscionability involves: a relationship that places one party at a “special disadvantage” vis-à-vis the other; knowledge of that special disadvantage by the stronger party; and the unconscientious exploitation by the stronger party of that weaker party’s disadvantage. 19 Chief Justice Kiefel, Keane and Gleeson JJ went on to consider the concept of “special disadvantage” making it plain that a number of factors must be considered in order to establish such disadvantage, that no one factor is decisive and that it is usually a combination of factors.11 Likewise when it comes to “knowledge and exploitation” it is necessary to consider the surrounding circumstances to establish the requisite knowledge of the special disadvantage and 6 FDN 62, see exhibit JPD-36. 7 FDN 3 at [49]. 8 (2022) 276 CLR 1 (‘Stubbings’). 9 (1983) 151 CLR 447. 10 Stubbings at [39]. 11 Ibid [40]. -- 6 of 7 -- [2026] SASC 48 McIntyre J 5 the exploitation of it.12 It is clear from the decision that whether someone ought to have known that another was subject to a special disadvantage and whether that person, knowing of the disadvantage, unconscionably exploited it, is contextual. 20 The respondent referred to Australian Competition & Consumer Commission v Radio Rentals Ltd;13 a decision of Finn J in which he considered whether Radio Rentals had taken advantage of a consumer with a special disadvantage. Justice Finn referred to authorities such as Amadio before considering the circumstances of the various impugned transactions. Justice Finn concluded that, whilst the consumer could be said to be in a position of special disadvantage, he was not taken advantage of by the respondent. In reaching that conclusion, Finn J considered, inter alia, evidence called from the various participants to the transactions as well as expert witnesses, a neuropsychologist and a psychiatrist to establish the context in which the transactions took place. 21 In the present matter, critical witnesses are dead, in circumstances where it will be necessary to consider whether Brenton Mayfield ought to have known that Grant Mayfield was subject to a special disadvantage and whether Brenton Mayfield, knowing of the disadvantage, unconscionably exploited it. That enquiry is not limited to the time following the diagnosis of ASD in February 2019. The diagnosis is in dispute. Even if the diagnosis is established, the question of whether the signs and symptoms were apparent to Brenton Mayfield is squarely in issue. It is therefore “on the cards” that the Ochre file, comprising as it does evidence of the late Grant Mayfield’s medical condition, presentation and history will be of relevance to key issues in dispute on the pleadings. 22 In the circumstances, I grant the respondent leave to uplift, inspect and copy the materials provided in response to the subpoena issued to Ochre. 12 Stubbings at [43]–[51]. 13 [2005] FCA 1133. -- 7 of 7 --