[TrumpyAl]

Thanks again for your input Jakeru. I didn't ever get to the double-checking part so I moved house without buttoning it back up. Comically, I moved 100m and it was all downhill so I actually physically pushed my broken Porsche from the old house to the new one! Yes, I did it in the milddle of the night so that my neighbours wouldn't line up and laugh at me :-]

I agree that I've not ruled this possibility out as yet. I was able to see the teeth from inside the cabin while I was turning it over via the bolt on the front pulley. I'm quite sure that I didn't go too far before moving to the engine compartment to eyeball the next set of teeth. And I used the timing marks on the front pulley as an indication of when I'd completed a full rotation. BUT, I need to measure the position of the teeth accurately, not rely on sight.

I plan to rig up an indicator of some sort, so that I know for sure if any teeth are even 1mm further from the sensor that the rest.

Access into the area behind where the starter is usually mounted is awkward, so if I'm not confident that will work, I may instead use the same indicator to enable me to accurately move one tooth at a time, and monitor the output of the crank sensor to see if it's changing state twice for each tooth. But that's definitely Plan B.

Fingers crossed!