I was talking to an elderly lady once who said they used to put a house brick in the oven then wrap it in a towel.
my nan did she never had hot water bottles
i was thinking that Chris. anything goes wrong with the thermost.and you have a bomb in bed with you.(Blimey!)
That sparks a memory of an immediately postwar device which was essentially a metal box with a electric light bulb in it. I think we had one but I never saw the benefit of it as far as I remember. Might have been regarded as too risky for a child.
And certainly wouldn’t have wanted one of those electric hot water bottles. Electricity + water + my precious person? No thanks....