I want an open plan conservatory - what are the issues?
The building regulations for an open plan conservatory are different from those for one that's separated from your house by a door or wall.
Where conservatories aren't separated from the house they aren't exempt from the requirements of the building regulations and that also means that removing any exterior doors or walls between your house and an existing conservatory will need building regulations approval.
This is to prevent excessive heat loss and therefore more energy being used to heat your home (plus higher energy bills) and also to make sure that the rest of your home doesn't overheat in warm weather.
As part of the building regulations approval process you will need to prove that adding the conservatory-type extension will not result in the conservatory or the rest of the house being less energy efficient than it was before.