Thanks for your replies I think Pirate Pete has got it! I just googled and Bass Straight Boats have a new rescue boat based on a 1960's boat which looks similar.
My boat was fitted with a shaft drive and the engine sat in the centre of the deck under the floor. Not sure what type of engine it was as it was removed a few years prior. I have decided to put a johnson 225 outboard on the back. To do this i have a pod being made for the engine to sit on and a bathing platform.
Should be ready in a couple of weeks.