In the Mutual Trust boardroom in Collins St, Melbourne, where a magnificent John Coburn tapestry called the Tree of Life covers a wall, investment banker Peter Yates decided to lobby Treasurer Josh Frydenberg the old-fashioned way: over lunch and a glass of wine.

On Friday, July 19, Frydenberg and about 30 business leaders filed past a grand portrait of city pioneer W.L. Baillieu into the discreet financial services firm's level-32 boardroom. They included Yates, a newly minted Mutual Trust board member, Liberal Party insider and adviser to Melbourne's famous Baillieu-Myer family.