Right, bit of an update....

I've sorted out the timing and the lights gone out. It turned out that the inlet timing was out by the smallest of margins - I took extra care when resetting it and made sure that the locking plate slid in and out freely after tightening everything up and turning the engine by hand a couple of times.

I spoke to a mechanic at my local Ford dealer about the tensioner, it seemed as though he was none the wiser about it! I had another look at it today and it seems to be doing its job, although the pointer has now gone past the window in the locking tab. I tried resetting it but it does the same every time, the tension seems right so unless someone tells me otherwise I think I'll leave it alone....

cheers,

Mark.