Before we could take the plans any further we needed to know for definite how close we could build to the drain. Baring in mind that we were told that they need 24 hour access to the drain for checks, maintenance etc it was stunning to find out that they didn't know for sure the diameter of of said drain and without that they couldn't give us an answer. The biggest indignity was that we would have to fork out £850 for them to send a camera down it to find the answer! If the drain was of a larger diameter we would only be able to build 4 metres from it unless we paid for a "build over" whereby they may let us build closer but on the condition we pay a further £850 at the end of the build to make sure that we hadn't damaged the drain & sign something to say we would be responsible for any damage to the drain at a later date.
You can see the line of the drain on the right of the plot with the man hole covers shown with circles. Actually on the ground only 1 man hole cover was exposed.
We had no choice but to pay the fee for them to check the drain which probably took one man half an hour. We were lucky though, the drain was found to not be such a major one and we were granted permission to build 3 metres from the drain. A result but a very expensive one!!