Tailgate switch failed completely in the end, took off the tailgate exterior garnish panel, bought a new switch, checked it for continuity and soldered it in but still no joy, tried a different lock / actuator from the breakers - still nothing, even after trying a different garnish panel.
Took the car to Mark my local mechanic who fitted a solenoid at the lock and a remote control unit in the engine bay - I now have an extra fob to open the tailgate which works 100% probably saving me a fortune at an auto electricians π