Hi I have a house built in 2005. There are 2 soil pipe vents, both vent directly into the loft. One of them vents from the main bathroom into the back of the loft, and has been plugged with a polystyrene bung with BBA written on it, and the other one, which vents from the ensuite and the downstairs toilet, vents into the front of the loft and is just open. Sometimes the smell in the loft is awful and it can penetrate the house itself. Now that I have found out that 1 is bunged up anyway, can I bung the other one? Or are there regs that need following? Do I need an "AAV"? Thanks in advance. Paul.