Julian Cope presents Head Heritage

Oooooh, exciting. I'm off there (Anglesey, not Bryn Celli Ddu) for me hols in September. Read this free to DL book when I was there last year 'The Megalithic Remains Of Anglesey E Neil Baynes' https://archive.org/details/cu31924029933011
when I was there last year. The part on lost megaliths/tombs suggested that there were a couple of long gone tombs next to Bryn Ccelli Ddu, some of which, the stone was broken up and used for a bridge and field wall. Fascinating little book, well worth a perusal.