Hi folks! I have a question re rat flaps / blockers - can they be mounted on the exit side of a pipe? We have a rat problem and think they are coming into the house via the sewage system. We live in a semi-detached property and the rat people have fitted a non return rat flap inside our inspection chamber where the pipe leaves our system. Unfortunately this empties into a shared drain with our neighbour and we suspect the rats might be coming in through their outlet pipe. We'd like to fit another flap in our neighbour's pipe (with permission) at the exit end of her drain where it enters the shared outlet chamber as we suspect the pipe may be broken just beyond this point. Can you buy traps that work this way round on the exit? Cheers John