I'm looking at buying a house that had an extension done some time ago (before the current owners - some time between 1985 and 2001 as far as I can work out) which wasn't done to regs or approved since it wasn't mean to include a habitable room, only garage and stores and as such, the house should not have been sold to the current owners as a 4 bed, but rather as 3 bed.
The extension is a dining room, study and garage on the ground floor and an attic room on the first floor.
The current owners found this out around 2007 and have now correctly marketed it as a 3 bed, with loft room.
They have also successfully gained a "Certificate of lawful development" from the council, which as I understand it, means that there will never be a demand from the council to take down the unapproved rooms/extension.
Obviously I'll be going through this all with solicitors but at this stage, I just want a broad understanding of what this means. Googling has largely just added confusion...
I've been told by the estate agent that because the ground floor extension was build single skin, it doesn't meet building regs and therefore they couldn't get approval to offically count the 4th bedroom as such. I'm not overly concerned with that as such, but for example, if at a later date, I wanted to add a conservatory or attic conversion (to the original roof) within permitted development, would that be possible or would I need planning as if so, would it be likely to be approved?
This in in England (since I expect the rules are different across the UK)
Sorry for the ramble... thanks in advance for any help.