Sometimes it will start straight away and run perfect,
other times it cranks for 7 seconds and then starts, hunts a little, sometimes stalls, then seems to run fine,

Only fault listed is for CKP sensor, another garage had already tried a after market sensor, then when it went into vauxhall they fitted a genuine sensor.

Have scoped the sensor at plug and at ecu and it is getting the signal to ecu, but it still (sometimes) shows the CKP error code,

The ECU has already been changed and it was still the same,

Petrol and matches does spring to mind