My guess is that CountMike's advice above is quite enough. I pretty sure what you describe as "colder" in the UK is not too severe, and the real risk s is only in moisture condensation.
As an extreme case, I'll tell you of the only time I have had problems in this area. I live in mid-Canada. 22 years ago I stored a small computer in an unheated garage for about a month in January, the very coldest part of the year. Overnight lows during that time ran between -15 and -35C. When I retrieved the unit from storage I did allow it to re-warm back to room temps for a day. But when I started it up, it could not boot. Apparently the HDD had developed a fatal error - I suspect moisture inside the unit, but I don't know. I had to replace the HDD with another that I loaded with a complete backup / clone of the original. (Yes, I had made that for emergency use), and it worked just fine after that replacement.