John
The model is very similar in size and layout to my little Huntress, which features in the latest issue of Model Boats (or so I'm told…). Layouts in this type of model don't vary that much, so have a good look at how I did it and it will give you a few ideas. The motor is mounted at the front with ESC as close as you can get, to minimise the length of the main power leads. The receiver and, in this case, the Lipomonitor, are fixed to the bulkhead with Velcro. The LiPo battery sits underneath the cockpit floor in a plywood tray, and the rudder servo is mounted right at the back.

Dave M