A bitter legal dispute over a multi-million-dollar property in Sydney's Rose Bay has exposed a series of damning WhatsApp messages between investment banker Michael Rothner and his ex-wife, Lisa Rothner, which a judge found undermined Rothner's defense.

The case, centered on the opulent Villa Biscaya and its coveted views of the Harbour Bridge, involved allegations of secret tree-cutting on a neighboring property.

The Property Deal and Deteriorating Relationship

In 2023, David Waterhouse, an estranged member of Australia's prominent Waterhouse racing dynasty, sold Villa Biscaya for $25.75 million to Michael Rothner. Ahead of the settlement, Rothner was granted exclusive occupation in January 2024 to carry out renovations. However, the relationship between the two men soured after Rothner moved in.

The dispute intensified when trees on an adjacent property, which obstructed the view from Villa Biscaya, were removed. Waterhouse accused Lisa Rothner of being involved in their removal. Michael Rothner denied any knowledge of the tree-cutting and counter-sued, claiming Waterhouse breached the contract by withholding necessary renovation documents, causing financial losses.

Judicial Findings on Tree Removal

In an extraordinary hearing, the NSW Supreme Court found that Michael Rothner had indeed authorized his ex-wife to oversee the tree-clearing operation. Justice Pike's findings were heavily influenced by WhatsApp messages exchanged between the former couple.

In January 2024, Lisa Rothner communicated with her ex-husband about the garden work. In one exchange, Michael Rothner instructed, "Important - do not want anything left. Good to do Sun am when everyone away." Lisa Rothner responded, "Absolutely & we can't have any evidence on site… Mike it's just amazing." On another occasion, she wrote about clearing the area so there was "no evidence." Michael Rothner replied, "Pls make sure they take ALL rubbish."

Justice Pike found these messages were irreconcilable with Rothner's claim of ignorance regarding the tree removal, inferring that the work was conducted surreptitiously.

Gardener's Testimony and Cash Payments

The court heard evidence from gardener Gary Gibbons, who testified that Lisa Rothner told him the trees were removed because they blocked the view. When he questioned authorization, Gibbons stated Lisa suggested they "blame it on David Waterhouse." He also mentioned discussions about creating a "bodgy company" to falsely attribute the work to Waterhouse.

Gibbons, who refused to be directly involved, reported being paid $300 in cash, with an additional $300 given later. He testified that Lisa Rothner and a contractor, Al Shahwan, later directed him to assist in removing several palm trees, including one over 30 feet tall, from the neighboring property. Lisa Rothner allegedly watched the work from the Rothner property.

Gibbons recalled Lisa Rothner showing Michael Rothner the result, stating, "Look at what the boys have done."

Justice Pike accepted Gibbons' evidence, rejecting Rothner's denial and concluding he was "intimately involved" in the view-opening efforts. The judge described the tree destruction as "an act of vandalism unconnected with the carrying out of authorised works on the property."

Contractual Breach and Limited Victory

Despite the court's findings on the tree removal, Waterhouse did not achieve the outcome he sought. Justice Pike ruled that the tree chopping did not constitute a breach of the specific clause Waterhouse relied on to terminate Rothner's occupation, as that clause only applied to damage caused by works on Villa Biscaya itself.

Consequently, Waterhouse could not legally eject Rothner from the mansion based on the tree removal. The court found that while both men provided evidence that was met with "considerable caution" and adverse credibility findings, neither emerged as a clear winner.

Rothner's counterclaim for over $1.3 million in damages, related to alleged delays and increased costs due to Waterhouse's conduct, ultimately failed. The judge found that Waterhouse's contractual breach did not cause Rothner any quantifiable loss, as he would not have immediately undertaken the main house renovations.

Conclusion of the Sale and Future Proceedings

Michael Rothner eventually completed the $25.75 million purchase on December 17, 2025. The court has yet to issue final orders on costs, with parties directed to attempt agreement by August 20.

Michael Rothner is a principal at real estate firm AsheMorgan and a prominent figure in Sydney's Jewish community, serving as vice-president of Central Synagogue. David Waterhouse, a member of the well-known horse racing family, has been involved in previous property disputes.