Hi, Just a quick update. I have removed the BCU and ECU ready to send off to Callrova. When I had removed the BCU, I thought I would try the ignition to see what would happen. With the BCU removed, it made absolutely no difference - same warning lights on and same items still working. Very strange.
I have started to remove the headlining so that I can seal the sun-roof. Its not too bad a job and there is a detailed thread here to follow. Just a bit fiddly with lots of things to take off so that you can get at it.
The red plug on the ECU has oil in it, which seems to be a common problem, so once I've got it started, that will be the next job. I am going to try to see if the ECU is also full of oil before I send it off.
Once again, many thanks for everyone's help.

The crossed B means that communication with the BCU has failed. Why would you expect removing it from the vehicle to make any difference?
Good to hear that things are moving forward though. Best of luck with the headlining.