Graham,
I will certainly check that. It seems to have cured itself but I have been fidling around with the wiries. I'll echo what Keith asks, what does it look like.
Good question. I've not seen one. Just remember more than one other having similar problem and the sensor was no longer glued into the shroud around the ignition switch.
Also does that mean that any transponder fitted key will work (provided it fits in the lock?
No - has to have the right code...