Never tried it, but they are supposed to be perennial, so yes I think it will be ok to grow on this summmer. might be prudent to pot it on tho. Regards pruning, I'm not sure, but for starters it's always ok to remove any dead stems back to a bud.

are any of the seeds viable? could you grow some from seed just in case the old plant is not very fertile

Some chillies produce a bigger crop in their second and subsequent years.
Prune now to keep compact/in shape. Prune roots by one third, placing plant back into pot on fresh potting medium and top off with potting medium. Protect from frost and move into heated growing area in late March. Start feeding about six weeks later. Keep pinching out growing tips to keep in shape. It will start to produce fruit in later Summer/early Autumn (fall).

That's interesting St John - does that apply to peppers too?

Not sure, Sid. I'll let you know in late Summer when/if my peppers develop fruit.
I have two types of sweet peppers and about five hot chilli peppers.

Ok ;-) Just sowed my peppers on the weekend.