There's a very good site (www.classicaustraliantv.com) which lists Australian TV drama and comedy from the '60s and '70s largely, including a brace of sitcoms, none of which I've ever heard of.
One in particular which caught my eye is a mid-70s offering called 'The Last of the Australians' about a Garnett-esque family (although, if you read the article, the makers would justifiably refute such comparison).
The majority, if not all, of the show can be found on YouTube. It seems rather good.
Anyway, sitcom fans and historians should find the essays on the site most interesting!