On the Lansdown sun disc, from volume 11 of the Proceedings of the Bath Nat.Hist. and Antiq. Field Club (1906).
We collected with the greatest care every piece, however small, that could be found. Much of the gold plating, notwithstanding all the precautions we took, was blown away or lost, but enough at any rate remains even now to establish the fact that it was so plated.
So the disc was actually gold-plated bronze (contrary to my misplaced understanding that it was pure gold – still at 6 inches diameter that would have been unlikely..). It was found in one of the barrows about 200yds NW of the ‘Roman Camp’.
archive.org/stream/proceedingsofbat11bath#page/12/mode/1up
This includes a photograph of the fragments.