@EilonwyWithRedGoldHair
the Age Okd question about the boiler. There isn't a definitive answer, there's a lot to argue either way. The best thing is probably to try a fortnight each way with everything else being much the same & compare.
How old is DS? Any SEN?
if he's very little I'd tell him the bath is broken and take him in the shower with me.
if he's 3/4/5 I'd put a shower hose attached to the bath taps, (you can still get the old rubber ones that are cheap & just push on).
if he's older hed just be told. It's not an option.
if he is little & wants to play in the bath, look at getting a large baby bath to put inside the bath.
Have you seen the clear stick on film for windows? It's not that expensive & really helps with insulation.
Look out for special deals on boilers, I think with the move to heat pumps, you'll get some decent deals and it will save you money, so it might not take too long to recoup the money spent.