[woodcote]

If you haven’t removed the digital powerbase, do so. That should get the analogue base working at a decent speed with standard controller. To be honest, don’t try anything with the SCP until you have the analogue pb working perfectly with the standard controller.

The issue with the SCP seems to be that there’s an overload - removing the digital pb might help. As for the wiring, UK club wiring is common ground, Scalextric is common positive... I think Ninco and Scalextric wiring is the same (ie same wires on controller going to same bands on the stereo jack), but that is worth checking too - you may need to swap the banana plugs round if it isn’t.