After looking at this thread and searching everywhere else, I resigned myself to the fact that it would have to go to the dealer for the rear brake pads doing. Car is an 12mth old F11 520 auto, with 28k miles on the clock.
The dealer confirmed that the car needed to be connected to the ISTA to retract the electromechanical parking brake.
The damage? £250.00 exactly at Sytner Nottingham
. Took them 90 mins and I drank as much coffeee as I could, and used up all their internet for the privilege :-)