Okay - dont quote me on this...but...i have had a dash rattle for ages (folk on NAOISC have also complained about dash rattle similar to mine). Turns out that its actually the front wind screen (in my case) that reverberates in the cabin i.e., its slightly loose
and that it is a common problem for GDB owners, though not many people talk about it. I had my front windscreen replaced (insurance) after heaps of "stone chips" and the dull thudding went away.
Just a thought
