Thanks Cyborg I think i've just fixed it! Decided to disconnect and reconnect battery (in the slight hope it would reset something) When popping off the battery, of the 3 wires connected to the negative, one had broken away at the copper joint onto the battery (the smallest - akin too 13 amp flex size). Reconnected - job done! I do wonder when the time will come to be heat shrinking wires all over the place! Thanks for your help -