Pay me $10,000 per year (+/-; negotiable) and I will certify that I will not use any of these heaters, thereby providing carbon offsets for all of these fine citizens, thereby allowing continued use with a clear conscience.
This would send a message that Britons have 'rights', which is an idea that cannot be allowed to gain a foothold.
They would prefer to simply ban outdoor heaters while keeping tobacco legal but nearly impossible to use. This gives them greater taxation leverage.
The maintenance of widespread fear is essential, so every now and then the jackbooted AntiSmoking or Enviro Police will kick down the door of a pub and arrest all in attendance for 'suspected environmental law violations'.
Goebbels and Himmler would jump up and down with delight.