The electrical bits have now been crammed into the Slingshot and it's ready to race. Everything seems to have fitted and works, at least as far as you can tell without putting the boat on the water. It's chucking it down outside so I'm going to take the risk and wait until the race !
Somehow the motor seems to run smoother with the Viper speed control than the original one. I suppose that as this cost 2/3rds the price of the complete boat it ought to ! The tiny unit isn't difficult to hide in the hull either. The receiver was more of a problem, I should have spent a couple more quid and bought a smaller box perhaps. Still, it's sealed up in a plastic bag and stuffed in the side.
The original servo still works the rudder and plugged into the receiver as you would expect. I assume this is a standard unit, just with a moulded yellow plastic box rather than the normal black.
Anyway, it's back together, ready to race. I'll let you know how I got on on Monday !