I have a 1930s house where the bathroom/toilet was originally downstairs at the back of the house. In the eighties a previous owner had the bathroom moved to the front upstairs of the house. The new toilet has its own soil/vent pipe at the front of the house but the old soil/vent from the original (removed) bathroom is still present. I am currently laying a patio at the back of the house and would like to remove the old soil vent pipe and concrete over the hole. Is this ok to do ? Also there is an additional vent pipe from the inspection chamber which ends approx 6ft above ground level and does not appear to connect to anything other than the IC. Can I remove this as well and fill in the pipe hole with concrete ?