I am the OP of the resurrected message. If it’s any help to you I used Archoil and it rectified my EGR fault, still no recurrence.
Also, if it’s any help to anyone that stumbles upon this thread later, it was the adblue delete that stopped my regens which got resolved with a software mod.
However, it also killed my stop/start which I could not rectify, so if anyone has had an adblue delete on 2.0tdi ultra Audi A4 and managed to maintain their stop/start please let me know where you got it!