Chris and JB, cheers I'll check these out. Funnily enough, I just put the Original Huge battery back on the car (now I don't use the K&N kit which needs a smaller battery for space).
Haven't had the car out yet, but I thought it may be down to a lack of electrical power of some sort.
This prob only started now the weather is worse and I get stuck in jams (won't charge the battery well) and I'm using a lot of lights, heater blower, rear demister wipers etc. all the time.
I'll let you know what happens.