The following websites may be of interest (click on the site name to be directed to the website);
This website is an on-going project which was set up to photograph and record all the leaf mining fauna which occur in Britain. A very useful key is included for Lepidoptera miners.
A comprehensive site which covers solely the mines of British insects. Over 1,100 species are described, with a key based on host plant.
An excellent resource covering all aspects of leafmining insects, which descriptions and images covering Coleoptera, Diptera, Hymenoptera and Lepidoptera as well as other causers.