BOX SHRUBS

Looks like lack of moisture, Ballethoo. I would remove them from the pots, prune off the dead parts, give them a good soak and re-pot in new medium. Keep them sheltered from wind and they should start to sprout again....they are very slow-growing though.

Thank you Janey. I have kept them well watered though. Other suggestions have been wind damage (so now I have moved them to the back garden) or lack of nitrogen. I think I will try your suggestion though and re-pot them. Thanks.