Hello Peter, thanks very much for your response. The site was a small patch of grass verge in the Chilterns (SP8041501733) which is left unmown through the summer for wild flowers. It is on chalk and bordered by gardens and arable fields. There was only this one retreat and I was rather reluctant to take a specimen, but I did take some photos (on film, so there will be some delay in getting them back) which I'll post if they come out. Meanwhile thanks again.