Many thanks for replying and for your advice, I have taken it on board, if you pardon the pun!!!

Geoff, not too sure about the scale but suggest it is about 1/12th. Regarding motor, I use an MFA Como drills 850 on 12 volts. This gives a nice planing performance but is not ludicrously overspeed for the type of boat. The propeller will also be key to the performance. I used the 2 bladed one that came in a package with the motor and speed controller. Peter