Harry O;
Read the London area NOTAMs for any day of the week, then fly over and look out of the window. There are thousands of cranes, and hundreds of NOTAMS. It would be impossible to do anything like you suggest. Just to add confusion the NOTAMs are not in any decent order with some showing LHR airspace, some LCY and some just a London Lat/Long.
The number of crane NOTAMs now is ridiculous and really deserves a section just to itself.
SND