Solved. Marco has it. At some stage someone has swapped out the crank position sensor and left the old unit hanging about in there. The actual unit was JUST visible at an almost impossible angle, tucked up under the assorted cables & "stuff". The lead went down behind the engine upper mount plate ...

Pictures always help but without removing the airbox, not easy. These are as good as I could get with a 'phone.

http://www.bysonleather.co.uk/Odds%20&%20Sods.htm

Sorry if this has been done before but I can't seem to find an answer....

Just below and slightly in front of where the the camshaft position sensor wires come from the sender a lead emerges from the cylinder head area and terminates in a 2 pin white male connector. And in my case that it all it ...