Rear electric windows and o/s/r door c/lock problems

hi all,

Can anyone advise :-

My Octavia Mk2 2007myr saloon has the following faults.

1) Both rear electric windows do not work from the Drivers switch pack ,,,,they do work if i use the switches on each of the rear doors.

2) The central door locking does not work on the o/s/r door, all other doors and the fuel flap work ok.

Looking at the wiring diagram there is a Convenience CAN bus, so i think the circuit works like this (please advise if i am way off the mark)...

1).The switches in the drivers switch pack signal the drivers door module (pulls resistors depending on up & down sw action),,,which then does some CAN wizardry......which is then sent to the Convenience control unit (not sure exactly where this black box is) ??.....then the Convenience unit does some CAN relay message work and sends the CAN data to the O/S/R door module and this is then converted to +12v and 0v to reverse polarity the window motor..... phew, now to isolate the part that is not working, i swopped the passenger rear door module (known good unit) with the drivers rear door module.....NO difference. Ok by a process of logic, it appears to be a Convenience unit fault as this the common device between the the 2 faults.....any thoughts ?

Note wires appear all good in door to jamb rubber boots so i don't think its a wiring fault.

cheers for any advice