the RHS says it can be cut back hard during the winter. But if you have new growth lower down then I'd reduce some of the older top growth now anyway. But you will loose flowers on that wood. I'd cut down to about 12" above the new growth.

Thanks Eileen, so if I cut the top branches to half now as the shoots are just breaking that will hopefully encourage more growth down lower?

Should do yes. But be careful if you are doing the work yourself.

I I Sir! That's what William always used to tell me. Sit down, slow down, and be careful!! When I sit in my arbor now for a little rest, I can hear him saying That's enough, sit down.

I expect it will make a lot of shoots at each cut - these need to be thinned to just one or two or you will have a whole forest of them

I Think this is what has happened over the past years, I always take a lot off it at Harvest time to decorate the church for Festival and the whole tree has got a bit top heavy.