Since i fitted larger wheels with thinner tyres there has been an annoying rattle over rough roads.
It was very occasionally there even with regular tyres.
These things are very difficult to isolate.
I had strips of sponge,fluffy toys packing the spare wheel,(bumpostop) 3M pads etc with moderate success.
I discovered what it was today.(Hurrah and ginger beer for all)
The rear hatch (coupe) closes on 4 rubber bump pads 2 at light level,2 lower down.
The lower ones were causing the problem.
the lower buffer is mounted in a socket with 4 prongs around the periphery.
The buffers (and their mounting have side to side movement.This (in my case was causing a drumming rattle occasionally,not all the time.
I mounted strips of double sided tape around the edge of the socket that holds the buffer.
edit :The slightly spongy tape,and I left the covering on one side of the tape
You probably cant see it in the pic but the 4 prongs were digging in to the plastic bumper at various points,
The noise is gone..for now.
I could maybe have cut away the prongs a little but I didnt want to weaken the fitting.
I can even hear the ticking of the cloc..oh wait thats RR,
its a lot quiter and any rattle makes things seem worse anyway .
edit: last 2 pics,I knew it was between nos 99 and 103