BV for a minute there I thought you had got into some classic 60's Julie Driscoll rock culture

But I am shocked that you used an ordinary bottle of water on the fire, you must have had a bottle of Italian wine on board

As Gadge says it is most likely the wheel bearings unless the car is not used too much and the brake cylinder is seizing. If it is the brake cylinder then it may free off then probably leak brake fluid. If it does still bind you can produce enough heat to boil the brake fluid and loose your brakes altogether.
If it is the bearing breaking up then you get the double whammies of the heat from the knackered bearings and as the the brake drum goes out of alignment the heat from the friction on the brake shoes so it will only get a lot worse. You could probably drive it in short bursts then a rest but 18 miles could take some time.