Thank you for your response.
The ignition timing is controlled by the powertrain control module (PCM) and cannot be adjusted therefore any errors there shold only be within the PCM or relevant sensors.

The camshaft timing is by chain, therefore with no belt, belt displacement is not possible.

I think air is getting in where it shouldn't or the PCM has developed a fault.

I am determined not to let it get the better of me, unlike the Ford main dealer!!!

Thank you again for you input.

John