I started this week by modifiyng the connection points of the new control box panel switches so as to match the connections from the control box.  Some alteration to the wiring of the control box is also necessary, due to the slightly different dimensions of the new switches.  I decided the best way to do this was to mount all the switches on the support panel first, then fit that and complete the wiring after.  In between doing this, I decided that the battery cable problem (too short) would be simply solved by mounting an isolator switch to a bracket bolted through the bottom rail of the body frame, just to the rear of the front O/S wheelarch.