Thanks very much for your help with this, I've just done a bit of researching on the web and it sounds like that is what she has got.
Only a couple of things, last year when the vet came out (thinking it was strangles) she opened up the lumps and loads of puss poured out.....this year they are...
I have a pony who was left to starve in the winter of 07, she was severely amaciated and in a bad way.
She is now practically fully recovered and a happy mare.
However, in May last year i moved her to a different field. After about 3 weeks these huge lumps came up under her chin, at first...