In the Herald’s story on the Wilson decision, they report:
Sir David is a lay person, not a lawyer, but during his inquiries into the complaint he had the assistance of a former Chief Justice of Australia, Murray Gleeson.
Not a lawyer? Well Sir David Gascoigne has a Master of Laws degree. Perhaps he never practised? But as he was Chairman of Minter Ellison Rudd Watts, I guess he is a lawyer after all.