I recently purchased a flat which I knew had an issue with building regulations which had been passed, but should not have been, for a bedroom with no external wall. Since moving in, it looks like there are several other things which should not have passed, i.e. an internal wall has been used to separate our flat from the one upstairs (where their staircase runs up the side of our bedroom, meaning we can hear every word/noise etc) which originally formed part of one whole house and it doesn't look like any sound insulation has been put in when the conversion took place. Has anyone any idea how or if I could follow up on this? The conversion of the building took place approx 4 years ago by the previous owners. The people who bought the other flat complained to the council about the granting of permissions which should not have been and the council just said they would have to sue. Anyone know if this would be the only course of action available? Thanks.