So nice to have it fixed and running tip top again.

Only for something else to fail and stick it into limp mode

Glow plug control module has now failed. Cleared the code and running fine again.
Hopefully just a glitch with all the ecu and mechanical work.

Jeep part is £140. Mercedes part £95.

Only 2 10mm bolts to remove engine cover and 6 8mm bolts to remove bracket and unplug the module and stick the new one in so if it flashes up again at least it's easy enough for an idiot like me to do