I'm running 100 mm soil pipe as data cable conduit between several outbuildings, and at one point need to go under floor level between two walls at right angles but differing heights - access is very difficult but I should be able to core drill the walls.
I seem to remember there is a flexible / corrugated version of 100 mm soil pipe rather like land drain but without the slots, but google fails to reveal a source - I probably only need a metre or two. Any clues as I could hopefully pull this between the holes??? (The short versions for 'back of loo' are far too short)
AWEM