Have you considered Warrnambool or Port Fairy - or am I way off the mark here? We had a very enjoyable 3 week stay in the Fig Tree CP in Warrnambool and also a week in the Big 4 in Port Fairy. If you want to go a bit further west into SA then consider Beachport SA or even Robe.
Cobram which is north of Melbourne is another favourite of ours. The RACV resort there is great.

Thanks for the suggestions, we really like the Hopkins River Caravan Park, it is a little out of Warrnambool but is nice and quiet with really good facilities. Close to the river so we can launch the tinny. We also stay in Port Fairy at the council operated park, not sure of the name but close to all that Port Fairy has to offer, love the churches there and there is a fantastic cafe overlooking the beach, you do need to drive to this though. Haven't been to Cobram for quite some time so thanks, we will maybe head there for a break.
Cheers

try edenhope or harrow, nice little towns.