Why I'm procrastinating over cooking

This is on the wall in the kitchen. Funny angle. It reads a mite over 5°C. It was just below five, but now I’m frying stuff and that makes a small amount of heat.

This time six months ago, I’d be sitting out in the hammock as the day starts to draw to a close. <sob!>

This is on the wall in the kitchen.

Given comments elsewhere about rurality – Solid stone wall?

Standard insulation method is, I believe, to add a plasterboard inner wall (with foil reflector surface)¹ and pin insulating material between the real wall and the new liner.

¹ Assuming such things exist in your locale

Solid stone wall?

Solid stone on the outside. The kitchen is one of the newer (thinner) walls. It is only about 60-70cm thick.¹ This is on a sort-of-cement interior wall.

Standard insulation method is, I believe, to add a plasterboard inner wall (with foil reflector surface) and pin insulating material between the real wall and the new liner.

The newer work (bedrooms) was “dry lining” which is, as you say, a plasterboard inner wall. No insulating material. In this type of house, you do not add insulation. The wall needs to breathe, not have insulation stuffed all over it.
No, we aren’t damp-proofed. The wall was built hundreds of years ago with this in mind. The quickest way people (usually Brits) compromise the structure of old walls is that thing where they drill holes and push in some sort of plastic gunk to make an insulation layer.

¹ WiFi reception is poor in the bedroom, only maybe seven metres from the Livebox, because a metre and a half of that is a very solid wall. The original gable end, from 14xx or so, before they even had right angles sorted. ;-)