We've been corresponding with Tim about this confusing site which we put up on our website as Circle 278 http://web.ukonline.co.uk/megalithics/wales/circl278/c278main.htm
our GPS fix for the centre of this site is SH 72202 74630 with an expected accuracy of about 3m.

A search on CARN gives RCAHMW entries for a prehistoric circular enclosure at SH 7223 7463 and a "circular feature" period unknown at SH 7220 7465, the monument we photographed is almost certainly one of these. We wasted a lot of time looking for evidence of a stone row.

The "real" Circle 278 described in the Griffiths paper and illustrated in "Prehistoric Wales" by Lynch, is the ring cairn spotted by Tim and listed by RCAHMW at SH 7216 7457, Tim's photos match the description and the illustration perfectly.