Are you sure it's not a gall? Some of the eriophyoid mites produce galls on lime like this.
A gall may well be the answer. It does not look like the two Coleophora species (I know about) that you may find on Lime. The answer would be to breed it through and see what you get.Sorry it is taking so long to answer, our inter-net is inter-mittent! A nice BT lady is trying to sort it out.Ina
Many thanks to you both. Very interesting and instructive and there are some good photos on the net that look like it. Quite a learning curve! I've already pressed the leaf so don't think I'll get an outcome by trying to breed it on but next time I'll give it a go!Carolyn.