Hi there, this isn't a seriously panicked question or anything like that, it's simply something that I have noticed over the last few days, that I ought to get some opinions on, since I'm kind of new to ball python ownership.

I've got a young ball python that I bought from a respected breeder about a month ago now, he/she (not gendered yet) is about five months old, a nice, healthy size, eating well every 7-10 days, friendly, clean, sheds normally... about as normal and healthy as I can really determine he-she possibly could be at this point. (And gorgeous too! <3)

I keep him/her in the recommended size tank, which is heated by an under-tank heat pad (temperature regulated of course) that covers the base of about two thirds of the tank... the ball has good places to shelter both on and off the pad, and up until a week ago, seemed to be regulating his/her temperature well by moving from one side of the tank to the other. However, for the last few days, he/she has been favouring the cold side of the tank, lying there against the side wall and getting quite cold to the touch! Keep in mind I'm in England, so temperatures here are quite low at the moment, even inside the house... the tank's air temperature is quite reasonable, but, I suppose being a new snake owner, I'm just nervous about why this might be! The snake is still lively and seems bright and alert as normal, but... I just want more experienced opinions that everything is okay here. I trust the snake to know where to lie and all that, but still... I'm sure you all understand what I'm talking about. New owner jitters and all that.

Thanks in advance for all and any advice!