should be a bit milder in the next few days so you could still do the re pots next week once the threat of frost is less. Just don’t prune a lot of roots, and keep some of the rootball untouched if possible. I do not add any fertiliser until the leaves have opened and hardened off. There is no real need as they should have enough stored energy to sustain growth until leaves are open and able to photosynthesise.
I am in North Dorset and we have had frosts for the last 4 or 5 nights but only light. Hopefully, tonight will be frost free,