Strange error:

When the engine is started and even before driving off, the ABS/PSD error shows in the digi display, RDK error, Brakepad warning illuminated... Airbag error....Crazy stuff. Power checked and that all seems ok.

After some serious struggling the puzzle was unraveled. The TT was out and so the driveline was lowered and cables disconnected. The ground in the boot section where the connections are was not connected at all and also a plug was connected wrongly. Almost all vanished when the connections were done right. Not the airbag. that needs a reset due to power failure. It is normal warning that will not go away when the ecu is unplugged. Reset is over the diag bus.