Coflein has decided to start working again (if it had been working on Friday then I wouldn’t have been walking round in circles looking for this circle yesterday!) and here’s what it has to say about Y Capel:
Circle of 54 stones, 38 of which were visible in 1980, the remainder being confirmed by probing, one stand over 0.4m high.
The all important bit of information I was missing is the eight figure grid reference: SH99950005