Four years ago I had a double garage built on the side of my house with the intention of making an extra bedroom above it at a later date. I obtained the necessary planning permission, had all the searches done at the town hall and the foundations were checked by a council inspector. They’ve now discovered that the garage is built over a main drain, so I can’t proceed. The council is blaming the architect and vice versa. I would have moved house if I’d known that an extra bedroom was out of the question.
It would seem on the face of it that you should be able to claim compensation. You will have to establish negligence on the part of the council, the architect or the builder: perhaps all three. I think however that you will need detailed help from a solicitor to establish blame.