The usual advice is to leave cutting back until Spring. the stems protect the plants during the winter.

In this wind you might find they break anyway. I cut them back half way.

I also cut them down by half whether it is windy or not. I use the decent offcuts to make cuttings and new plants for next year.

I leave mine until spring, cutting back just as the new shoots start to appear. doing it this way helps protect the plant during the winter

Thank you for all your help.I will cut them half back and try for new cuttings.