Thanks Sam, I've just started it and battery was OK, took the second start up to get EPB off. The park off button does work but it doesn't deactivate the EPB unfortunately. I look forward to using a trickle in future ad giving a whole days charge to see if that helps the EPB deactivate upon ignition.
New problem, This button has always been loose and now it's fallen off into my hand. Cheapest on ebay is £199 delivered for the whole unit but it's in beige. My interior in black.
Or I wonder if you could just swap the knob from a QP one?