Thank you Mamya I was just looking for that.
This came up on the Rick Stein Cornwall programme. It's connected to Tintagel and a strange very old railway train.
My mother always said that whoever wrote that song had never visited our house where, irrespective of the position of the damper, most of the smoke from our coal fire ended up in our living room!
The back boiler in our house was totally unusable, so bath night always involved my mother filling up bucket after bucket of hot water from the 'copper' in the kitchen and carrying it through to the bathroom (which, fortunately, was also on the ground floor).