Thanks, Kate. I've been using FreeBMD but that hasn't come up for me! It's very odd. But now I have viewed the image for Margaret and the smudge is obviously causing the difficulty.
FMP have a typed entry:
https://search.findmypast.co.uk/reco...2F000508%2F016
Vol 26 page 753
John Williams is for the only time in his life entered as John William, without the s.