I would leave them till frosts kills off the leaves. I have seen a lot worse eaten Hosta! Yours are not that bad.

Mine look like that now K'gran, I always let mine die down naturally then pop them in a sheltered spot for the winter months.....

late autumn to mid spring is the best time to divide, so not quite now.

Thank you all the advice I needed .

To prevent munchkins getting at mine I have put them in fence mounted containers(see my photos)and very successful it is to.When they start to look past their best I take them down and cut them right back and if I think they need splitting, I tip them, out ,put a spade through them and repot them, ready for next year.I personally feel that leaving them delays the inevitable,their not going to get any better are they?So I am not left with a void I put up my winter ones already planted with Lemon Beauty box,Pigface,variegated Hebe and crocuses.If splitting up in Spring works for you, stick with it,kerryvw.