This may affect others at some point and while I am convinced it was not the cause of the origional mechanical problem with the gear box I am sure its caused the long running issue with programing the ECUs.
Feel free to read the whole thread but the short version is I removed all my kit last week and replaced the OEM head. After that the local garage was able to reprograme the ECUs which they where unable to do up until then.
The reason.... according to the Vauxhall 'flying doctor' from Luton the head actually is also an ECU ( not just the display ) and with out it some of the other ECUs can loose their SN / Chassiy numbers ( a known problem by all accounts ).
Now I have not been able to get this in writing ( although I will try ) and I have not been able to talk to the Vx guy directly my self but I spose its plausable.
On that basis say in 20 years time there is an ECU issue and your original head is long gone you may end up throwing the car away as a result. You may laugh but running through with the local engineer he said in that case you'd have to buy another head.... been 20 years on it would be good luck if you did - never mind one tech2ed out correctly.
So if you have a Veccy ( and I recon this is a face lift thing been fully canbus ) be warned....
I'm lucky - this is warrenty work others may not be.
Can any one find a way to confirm this ?