Knocking noise diagnoses help please.

[sbcb]

Gidday all I would really appreciate some technical feedback.

Car AU1 V8 Ghia IRS 130,000km
Recently had rear lower control arm bush repalced R side
New KYB gas shocks installed (1 week ago) Upper shock mounts appear good.

and just now replacement rotors and pads all round (stock brake setup - used brembo rotors and bendix pads).

Had a lot of trouble getting the rear discs off and bent a handbrake pad clip in the process (not broken though).

Since the rear brakes have been done have had a rear end knock (appears to be the L side) at low speed (0-50kph then nothing after that speed). Its a constant knock, knock, knock. Applying brakes doesn't affect the knock and no vibration can be felt through the car or pedal. Shifting the car into neutral to coast doesn't affect the knock.
* Pulling the handbrake up gently makes the noise disappear while coasting, then returns the instant you release it.
Hub/disc and alloy surfaces appear clean flat and well secured. Alloy nuts are tighten enough (though not touque checked).

I have just taken the L side rear disc off again, cleaned and checked everything and bent the Handbrake pad clip down further (the pad still has a slight 1mm play in it from alloy to hub, Does it need to hold the pad firm against the hub?) I didn't see any signs of wear of anything rubbing or knocking).
Test drove it around the block after this and it was gone (rejoice!) used brakes a few times, checked handbrake was holding - all good).
Just went into town (12km cruise) while slowing down it was back again (knock, knock, knock, @#$? it).
It is slightly speed related (the speed of the knock) but doen't seem to be being happening as fast as the wheels would be rotating, and isn't going hard out at the 50kph mark, just slightly faster than 10-20kph.

Posibilties
- Handbrake pad causing issue somehow & pulling it on while coasting tightens it up.
- New disc slighlty warped and as it heats up causes knock
- axel, diff got upset when the old disc was getting belted for being stubborn (though I thought these problems wouldn't be so intermittent and the slip into neutral and coast doesn't affect it at all).
- bearing
- radio not loud enough

Any thoughts would be greatly appreciated team.

Gunna sleep on it tonight and give it the fresh perspective tomorrow, I don't see how a little 1mm play in a handbrake pad is responsible for this solid sounding knock.

Carl :