Hi, when doing MOT brake test on the rear brakes they were both holding on slightly, 40-50kg load, for about 5 seconds and then released.
TRC OFF button was activated to disengage the ABS etc.
I won't bore you with all the investigation and part swapping but nothing had any effect.
There were no vehicle testing advice details when logging on for the MOT.

I called Toyota tech hotline, very helpful.

By activating the TRC OFF button does not completely turn off the ABS system. We used Verus to put the ABS system into INSPECTION Mode, this then gave us perfect readings and no holding on.

Hope this helps someone in the future and avoid the time wasting.

Martin.