They're a bit of over the top Occa, it's not Victorian per se, even though it takes place in Victoria. They could be in WA and still sound the same.
I know its stylised humour but go to some of the specialist places in Chadstone shopping Centre or down Toorak Rd and you hear Sue and Pru.
And other places in Melbourne have Kim a plenty.
From Frankston to Kew to Warrnambool the accents vary greatly. The newer academic accent is another one, hybrid American / Australian mostly spoken by females, with "yaar" and "amm". But I get your point around the similarities per state.
The same goes for NZ, I notice a difference in the north island from the south or more specifically Wellington and Auckland vs Christchurch and Dunedin.
Just saying.