Hello John, the cam sensor is on the bulkhead end of the l/h (passenger side) camshaft/head. Check its plugged in. Its a round alloy "cup" with the sensor inside.held on with a couple of 10 mm bolts I think.
I have seen may of these go faulty.Check the wires for the insulation rotting off. If this is faulty the car will not start. If the sensor goes faulty when the car is running it will not stop the engine.
I remember the last one I bought was about £130 !!
Square wave signal switching to earth , if you have a scope.