Update. Just got the Mog out of the garage to go to play golf. Tested the handbrake locking on.
Cold start, me in the seat, no seatbelt. Handbrake locked on. Warnings activated.
Seatbelt in, handbrake released so car moved.
Engine still running, my seatbelt not in, handbrake did not lock on. It appears the system cancels after the initial locking on.
I'll try the effect of the footbrake and auto lock next time.