Many thanks to everyone for their advice, it's really appreciated. I can't believe I've got away with leaving my Hostas in pots for about ten years! They have done very well but I suppose they would be bigger now if I had divided them. Even so, they look lovely in pots on the patio. I think I might take advice from obelixx and divide them in the spring as it gets quite cold and windy here in Lincolnshire and I don't want to lose them,also it might give me time to build up my muscles in order to tackle them - wish me luck.
Intended to buy some new hostas earlier in the year so will now seek out some recent introductions. There are some nice small varieties now too.
Agree with Mattbomsai1 about leaving divided clumps unpotted over winter. I do that too.
I've done that. Only because I forgot them. They stayed in a trug in the shed. They were fine and at least slugs didn't find them.
I bought some hostas about 4 years ago and put round my pond - reading above I really wish I had split them earlier because I think they MAY be a little tricky - biggest one is 3 ft in circumfrence. Oops. As I am doing it single handedly it will be an (erm... challenging) experience. Oh well its going to rain so at least the soil will be easy to dig!