The handbrake on the Mk3 is an inboard drum brake that sits within the disc inside the wheel hub. The problem I have encountered, I am sure relates to the hill hold using the discs and the handbrake using the inboard drum.
If you stop on an incline with your foot on the brake and apply the handbrake, when you remove your foot from the brake pedal the car will 'drop' onto the handbrake after a couple of seconds when the hill hold lets go. I suspect this is why the car is susceptible to creeping on the handbrake.
There is no way to park on an incline other than riding the clutch to a standstill (which seems all wrong to me) and applying the handbrake, or timing applying the handbrake while rolling to a stop to avoid the hill hold kicking in.
