Crank sensor or phase sensor (check the wiring inside the dizzy as it rots).

From the diagnostics in the other post :

9) Turn ignition off, unplug ecu, turn ignition back on (don’t forget immobilizer if fitted)
10) CRANK SENSOR: Check resistance between pins 3 and 4 between 300 and 1200 ohms.
11) CRANK SENSOR: Check AC voltage on pins 3 and 4 while cranking engine - should be at
least 2V.
11) PHASE SENSOR: Check resistance between pins 5 and 23 between 300 and 1200 ohms.
12) PHASE SENSOR: Check AC voltage on pins 5 and 23 while cranking engine - should be at
least 1.5 - 2V.