Took her to see Jane, the vet, this morning and she agrees, it has grown quite a lot and is actually affecting both sides of her jaw as well as her chin, but she felt, that as long as she was still having quality of life (which I do think she is - she's eating ok and has actually put on weight, and is bright in herself) that we just carry on as normal (ish!) until such time it really impacts her quality of life. There's no infection inside the mouth at all and Jane didnt think it was actually causing her any pain.