Thanks for the info.
As far as I'm aware there wasn't any planning permission required/requested for the original one. The sellers when we bought it were executors on behalf of a deceased owner, and we did bring it up but our solicitor mentioned he had no concerns as it had been there at least...
We've got an existing side conservatory 4.6m x 1.3m. It's built from a short concrete block wall of around 70cm with upvc windows on top a short timber frame around the windows in the corners/top and a polycarbonate sheet roof. It's still got the original exterior door opening between the main...