Think maybe I wasn't clear. We're not proposing to build over it. We would be building down the side passage which would block access by a vehicle although it would remain accessible on foot! I'm thinking if people can put them inside a house then it isn't necessarily a problem?
I'm thinking of extending to the side of our house, but there is an inspection chamber in the back garden. Can I do this without moving the inspection chamber or do I need to leave access for machinery?