Yeah, it's not great... The CEM went back in today. Not before I isolated the base of the affected pins with some heat shrink to minimise stray currents and then coated the base with lithium grease as shown in the pictures to protect the area from oxidation.
No change to my idle symptoms and I don't have the facility to check the trouble codes myself. That will have to wait for the time being.
Car feels much the same to be honest. Perhaps my clean up the circuit board had no positive affect and the solution is a donor cem.
Bit of a dead end at the moment.
https://ibb.co/vPH9Gc3
https://ibb.co/WzGH8QS