Koalas in the wild around Melbourne

Apologies for this not being a birding question, but local birders are
likely to be able to provide an informed answer to this enquiry.

I have been asked by a soon-to-be visitor to Melbourne where he and his wife
might be able to find a koala in the wild.

I have seen them many times over the years when birding at the You Yangs and
there are regular commercial tours there which show visitors koalas
previously located by specialist “koala spotters”. However their numbers
took quite a hit during the drought and they are not easy to find these days
without “inside knowledge”.

Can anyone suggest a reasonably reliable site for koala within striking
distance of Melbourne which a visitor could go to with a good chance of a
sighting?

Thanks for any suggestions.

Richard