The tech support feedback from OMEX advised aiming for a gap between the VR sensor and the trigger wheel of 0.5mm, a fair bit less than what I had. Adjusting this clearance was achieved by removing the sensor bracket and adjusting it with a large vice and hammer. On the test rig (see photo) the ECU now reported the correct engine RPM, so a second attempt was made to start the engine. This produced some startlingly loud bangs from the exhaust, and investigations showed that the ignition timing was 180 degrees out. Swapping lead pairs on the coil pack quickly rectified this and the engine finally attempted to run!

To say I'm pleased is a bit of an understatement. The real test will come when it goes for mapping, which is booked for the 16th December. The main thing I need to do before that is get the lambda boss replaced in the exhaust. It's completely rusted up, which is why it needs replacing. It's all starting to get quite exciting!