I need more space in my home. I live in a mid terrace with a large garden, and a kitchen and bathroom ground floor extension which leaves a dead space in the side return. Ideally I'd love to knock down the outside wall of the kitchen and extend sideways but budget atm doesn't allow for this. The build would go right upto next door's external kitchen wall. Is this allowed? Others in the street have done this but don't know how recently. Any advice or thoughts on this gratefully received.