Mr Guppy is unbelievably ignorant of just how lucky he is in FAAland. If I want to fit a Tanis heater to my UK engine - totally independent of any aircraft systems - I have to submit a mod including the the full spec of the ins and outs of a ducks backside, a blank cheque and an open-ended completion date expectation to EASA for a total benefit of perhaps 14 days extra flying days per year, 13 of which I cant get to the airfield which wont be open anyway. We dont bother with winter prep like preheating or airfield clearing because its just not cost effective or worth the bother to anybody in the UK. Only just a couple of years ago the run-up to Xmas was T-shirt weather - what use a preheater then?
BTW, interesting reading - manufacturers recommendations & SBs etc suddenly becoming gospel when previous recitations on various subjects made us believe he knew far more than Messrs Lycoming & Continental.
Also BTW, my hovercraft has heated windows and a squiffy heater unit, so I'm fully prepared. The eels can stay outside.