Wrong end of the year I'm afraid, but yes, they certainly do respond well. I cut one back to about 3 inches in May one year (next door's ivy had been allowed to grow out of control in this neglected garden I took on, and the choisya growth underneath had about five or six feet of topgrowth, etiolated and growing flat along the ground). It responded very well - by end of summer, it was upright, bushy and about 2 - 3 feet high. I did one recently here where I live in the gardens of our flats - took a chance and did it early August, down to about 6 or 7 inches on all stems. Its recovered and growing - I just hope it hardens off properly before winter sets in. But I wouldn't risk it now, unless I didn't care if it survived or not...

In case you're wondering why I did the one in August - it gets too big for where it is, and the contract gardener had cut it with the hedge trimmer into a cube shape - it was dead ugly and reminded me of a wardrobe or bulky piece of furniture,I couldn't stand looking at it... I didn't care if it died either - it will always be too big for where it is. But, its responded well, so if I'm still around, no doubt I'll be doing it again in 2 or 3 years...

I'd wait till early May, do it then, and give it a good feed immediately afterwards.

I am not an expert like Bamboo but I had one at my previous flat. I didn't realise they grew so big and it really started to outgrow its place. I cut it right back and it grew back pretty quickly.

I forgot to say, it won't do any harm to trim it back a bit now, rather than a full heavy hard prune.

Thank you both so much! I did trim it back a little yesterday, but I was itching to do it much harder. I just wish I'd pruned it more often after planting it, to keep it more manageable. I just didn't realise how big it would grow. I don't want to lose it, so I'll wait until May and do it then. I've put a reminder in my phone!

Yes agree with bamboo, they respond very well to renovation pruning, but I would wait until the spring, don’t be afraid to go right down on it, cut it down to a nice framework and yes it will look harsh but many buds will form and before you know it, it will be back to its former glory, keep it to the size you want it by clipping it after flowering, do selective pruning and not shear it has this does not look good.

I have a big one near the front door which i have had 25 years. During that time I have cut it back hard almost to the ground and it has regrown quickly. I will be doing it again next year after a light pruning at the sides asap.