Thanks very much for the replies, I will follow up the information given.
This is the first electrical problem I have had with the Wisper; the previous bike, an Eco-Brand was an electrical nightmare. Wires pulled from the micro-switches because the cables were too tight, a broken start switch, the prong connections smashed in by the weight of the battery bouncing around on it, water in the control unit & pedal sensor, a blown fuse...
I have been using electric bikes for over 2 years now and had forgotten how slow and how much hard work a normal bike can be (especially when there is a strong wind blowing in your face). I also now feel extremely vulnerable on the road. Just pulling out of junctions or moving out to pass a parked car just seems that much more risky.
Thanks again.