I don't think people are allowed to fly over built up areas as you describe, at least not unlesss they are high enough to avoid them should there be a problem.
Personally I don't think governments should be allowed to prevent anyone from flying a homebuilt, like the helicycle, which in the UK at least is effectively barred by the system of approvals required(almost a certification) for issuing a permit to fly.
The Rotorway was first approved due to 'accumulated sufficient experience of safe operation, and has been shown not to possess unacceptably hazardous features.'
The CAA should allow us to go back to that standard for issuing Permits.
Or, if a kit is approved in one European Country, it should also be approved in all others.
Just my thoughts...