Yes I have seen the picture of the other boat in Sydney. It is a real mystery that there are three boats and don't know what they are!!
Thanks for the offer of help with the motor.
Luckily the impeller was changed in the last 12 months by the previous owner (I have the old one in the box of parts) and what looks like a new spare as well.
My boat had been used up until 18 months ago at Lake Eildon so it is in reasonable condition.
One thing that concerns me is there is no filter system on the front of the carbys. I'm thinking that would not be good for the engine. I'm trying to find the correct air filter for the three carbs. See photo attached