On 24/09/2019 22:23, David wrote:
Insulation requirements are below current - glazed with a plastic roof and
has a radiator in so is part of the main property - which wouldn't be
allowed by current regs.

If the previous owner has removed the original outer door
and/or wall so that theconservatory is part of the house
then this would not be allowed under existing Part L(2006).

If it was done after October 2006 then in theory you could
get the remedial work done and then go back and sue the
people who owned the building at that time.

Attempting to heat a conservatory is futile. You could
spend more money heating that one room than the rest
of the house.