[malky]

If you are parking your bike outdoors in sub zero temperatures, unless you " box in" the motor, any external heat from a low wattage heater will be quickly dissipated. In days of old I used to put a fireproof blanket around the engine of my bike with one of these paraffin sump heaters under the engine. It worked fine as long as the blanket was in place.

[Narada]

Now I'm liking that enfield twin propelled fun-mobile!  Does it steer and stop too?

[malky]

The Berkley 3 wheeler came with a 2 stroke twin as standard. The four wheeler had the Enfield super meteor motor in it. Uk licence regulations at one time allowed you to drive a three wheeled car on a motorcycle license. At one time you could pick up these cars for nothing so some enterprising individuals would put the meteor engine in the three wheeler, I sat as a passenger in one once and it was terrifying. Check out youtube "Berkley 3 wheeler" some nuts put an even bigger engine in one.

[malky]

A big thankyou to krimp, because I looked at one of the links posted in this thread the retailer sent me an e mail with their product list which includes a circulating water heating pump which I can use in my domestic system, without having to rip out half my kitchen. Great where these things lead.