SUAVs will not be a lot of use for delivering parcels if they can't fly over congested areas.
There is someone who posts pictures on the internet taken with a DJI quadcopter. It has been flown within 20' of the top of Blackpool Tower, which is 518' agl. There are other photographs from the same individual taken at about 2,500' above the town centre.
These are the sort of idiots we're dealing with.