3 SVs close to each other sounds like you are right on a 'T' in the watermain which I don't think the council would even contemplate moving TBH. Even if they did, the cost would be fairly high and they would have to break the water supply while doing it. You might be allowed to construct your driveway over them. Very often, risers are used to bring the turnkey on the valve closr to the surface for ease of access so lowering them would simply be a case of removing a riser and possibly replacing it with a shorter one. Any good plumbing/builder's providers would have these and a plumber or good groundworker should do the necessary.