Thanks for the replies, I had no idea there were any responses, I didn't get any notifications.
We found that someone had made an attempt to rid the robot of the T2 feature that had messed everything up. Removal of a couple of wires on the selector switch caused the system to not supply power to the correct circuits when switched , despite displaying the T1, T2 mode correctly on the UI. The joys of purchasing old used robots with no manuals...