Tidying up did cheer me up a bit. A bit more progress on sorting my knight's tour material might help. The problem is that I keep changing my mind about what is the optimal method of arrangement. The way it is going seems to be to place emphasis on the different types of symmetry rather than on the board shapes. Thus instead of having a section on rectangular boards it seems better to classify rectangular tours across several sections according to their symmetry, and whether closed or open.
I tried switching on one of my convection heaters last week but it produced too much smell of burning dust. So today I took it all to pieces and cleaned it internally. I'm sure it could be made to come apart more easily. So many screws to take out, and so many pieces, like the wheels, to remove before the actual bodywork could be opened to give access to the oil-filled radiator! Fortunately it all fitted back together again and it is now working OK without the smell. It was all a bit like playing with the Meccano that I used to enjoy as a boy.
There is a central heating system and radiators, which came with the flat, but I'm not at all certain how that works. I use it to provide hot water for washing, but hesitate to use it for the radiators, since I'm not sure how much gas it is likely to use. I expect a cold spell will be needed to stimulate me to try it out.