Keep them dry. If they get too cold when wet they may rot. They won't be growing anyway so won't need water.
I don't water mine until end of February or even early March, and that is only if the weather is mild.

I agree keep them dry. Its the cold and wet that does for them not really the cold. Most of mine are in the cold conservatory.

That’s what I thought but wanted to make sure. Thank you both for your replies.

Succulents from Mediterranean climates, such as many Aloes, Aeoniums, most Crassulas, Sedums, Echeverias, Iceplants, Lewisias, and Calandrinia grandiflora all need a little water and food in the winter, since that is their normal growing period. For these plants, wet heat is the killer, though it would be hard to get them hot enough in the UK. It would probably be too dark and cold in the winter--even in the summerhouse--to allow them much growth until spring, though.
Hywel and Sbg are both completely correct as far as cacti, Agaves, Adeniums, stapeliads, Plumerias, Pedilanthus, Pachypodiums, Jatrophas, Beaucarnea, and most succulent Euphorbias are concerned.

I agree, depends which succulents are in question. I have a couple outside under the snow right now which will come back in Spring (Sedum kamtschaticum 'Variegatum'), yet I have a couple in the house which are in active growth.