Selling our house and the buyers surveyor/solicitor requested evidence of a "Build Over Agreement" from the water company. This is in relation to a conservatory we built in 2007, which goes over the sewer running along the back of our row of houses. The sewer was left in place and the manhole, which is now inside the conservatory is capped with an air tight screw down manhole cover, beneath click together laminate flooring. 4 of the 6 houses in our row have the same arrangement with a conservatory or extension.

Due to a restriction on permitted development rights on the original housing development we had to obtain planning permission. At the time, neither the architect, planning authority or the builder advised we needed this permission. From what I can make out online, the water companies didn't take ownership of the sewer until 2011. So in theory we didn't need to seek agreement when we built in 2007.

Anyone able to comment or advise on this?

Not specific, but your solicitor should be able to arrange an insurance policy against possible future problems. Cost about £50...

These seem to be very popular these days for when a house doesn't have planning/building regs and all that sort of stuff in place, and keeps the legal chaps happy. Should do what you want I think?

Indemnity insurance has been quoted at £430! A con in my view, but will most likely have to be paid to get the same moving again.

What I'm interested in is whether we should have had any agreement in the first place.

Youch. We were told £50 as we didn't have all the building regs on a loft conversion. But the buyers solicitor never raised the query so we didn't get it.

What does your solicitor say? I can't see you could have got permission from somebody who didn't even own the sewer when the work was carried out? £50 is a cheap solution, £430 worth making them earn their keep!