Well, today is a good day.
After doing a pre MOT check it was found that the lambda sensor was buggered
so a new one was sourced and put in. Then there was a problem
it seems as though the same guy who fitted the previous head unit had also fitted a lambda sensor
Big big thanks to rubjonny for his help with the wiring diagrams and all is well again. Also turned out that the car was running really rich when idling so some lumpiness has gone. This now means that the fueling is sorted with the Corrado and will be (hopefully) a little easier on the fuel
Now it has another 13 months MOT on it and I suppose I'll have to tax it as well now
Going to pop into work in the morning to get the car inside and sort the broken passenger door handle and the faulty drivers window