Well now there's a story. Should be able to double seal it then leave it under the floor. Except the building control guy has been out to check the footings before we pour the concrete and said because the waste that runs under where the extension will go and is over 150mm we need a build over agreement. So I'm waiting on Yorkshire water to come out. Could be as simple as seal it, could be as bad as building a full new brick man hole at the side of the extension. We will see plenty of other stuff to do. Kitchen gets ripped out next week so I can knock a wall down. How I convinced Mrs W that it was worth being in one big mess all together I will never know.
Anyone need any soil