Look if you really want to be green then turn off your central heating and sit in a coat, sell your car which is worse than any patio heater (which is not for heating the world but to provide warmth to people socialising on a chilly evening though anyone with any common-sense would move indoors) then preach about green issues and banning this and that.
You here constantly about carbon footprints, wasting resources etc and see knee-jerk measures introduced that often cause more problems than were there in the first place! All conceived no doubt by car drivers, although in all fairness some will cycle with a car following behind
What I am trying to say is worrying about completely insignificant, tiny green issues such as the Chelsea Flower Show and patio heaters is a joke! Global planning is necessary and the combustion engine the first to go. Nuclear energy is the answer and electrical engines.
Colin