Thanks all. It is the metal clunk noise that I hear when releasing or applying the brake. It is very loud and profound when reversing or parking uphill or downhill.
Okay, this is helpful!
Might I inquire in which order you normally apply the brakes while parking?
I usually go to P (while fully on the brake pedal) and then apply the "handbrake".
This has never "unsettled" the car in any noticable way when driving off, whatever the incline.
Of course I do the procedure in reverse on starting up:
1) fully apply the normal brakes
2) turn the car on
3) move gear lever to D (or B)
4) release "hand brake"
5) release normal brake and drive
However, I've noticed the car to do a "jerk" when I apply the handbrake first before going into P e.g. at a railroad crossing.
So, I'm thinking the sequence of applying or releasing the various brakes matters.