Hi all Sometime ago I replaced a bathroom suite & during the process replaced the existing AAV for a new one as I noticed we were getting some nasty smells in the bathroom and the adjoining en-suite. Unfortunately this doesn’t seem to have rectified the issue & my thought is that perhaps the valve is positioned to low? I’ve attached a picture showing the valve. The valve is now boxed in & not easily accessible without removing tiles etc. I’m now looking to do some work to the en-suite which is the other side of the wall on the right as you look at the picture & wondered if I could put another valve on the horizontal soil pipe close to the en-suite toilet or does the AAV have to be only on top of the vertical soil/stack pipe?