Will chilli pepper plants from this year be ok for next year or should they replaced ?
The ones I have are in the green house at the moment but could be brought in doors if it gets too cold.

By chilli peppers do you mean hot chillies or sweet peppers.?

chilies may go on for some time but i would not bother with the bell peppers personally. I'd go for fresh seed and new plants next year.

Hot chillies are perennials...I found this out after I threw my plants away....drat!!

You may as well keep them going - if any of them don't survive the winter you can start some more early next year. My tabascos are doing fine on an indoor windowsill. I was a bit worried that they wouldn't overwinter in an unheated greenhouse so I brought them in.