Hi,
Yes it could have worn the high spot down, it doesn't take many miles.
Slack in the handbrake cables/mechanism should not cause your brake shoes to rattle against the back plate. If it was me I would have the brakes apart to check they have not been reassembled incorrectly/have springs missing or broke.
I assume you have tightened the handbrake cable up and the noise has stopped happening now. I believe that this is only masking the real problem. Compare the shoe/spring/handbrake lever arrangement with the manual diagrams. This sounds very dodgy to me!!!!
If you are unsure at all, take it to a garage/quick fit sort of place. Brake failure is no fun!
Regards,
Barry
I found that it was the shoes rattling yes. I did disassemble it all and it looked as I left it before the car had its MOT. I tried tightening up the handbrake but this didn't aid it.
What did fix it was putting another drum I had in the garage on to replace it, the sound vanished straight away even with the handbrake and the brake shoes adjusted fully loose.