Pot bound advice?

Hi

Please can you advise me what to do about my potted box plants. The wind smashed one of them at the weekend and I’m very disappointed. 

My question really is, should I get the plant back in a pot the same size or should I go bigger 

I think it’s going to be quite tricky squeezing it back into a pot the same size because of all the roots.

I thought I could remove quite a bit of the roots to get it back in a pot the same size. Would that be traumatic at this time of year? Not sure which is the best course of action considering it’s got quite a bit of new growth. 

Thanks