@MrsDB that's exactly what we had in mind. Its good to hear its been done before, but because we would have to remove the slab first it may be tricky…

Or maybe someone could just recommend where we should turn to dig into the concrete? Any pointers would be great

We are looking to buy a post war home in Holland Park which has a rumpus room underneath which isn't legal height. The rumpus area is divided into 3 rooms…