Parachute drop sites are a real problem for every airspace user. The circles on the map do not constitute the extent of the drop zone. Consider Weston for instance, there are occaisons there when they could be dropping outside the DA. At Sibson or Hinton I should imagine they regularly drop outside the circle; I would appreciate a comment from a more knowledgable party.
The other big problem is that there are many drop sites that are dispalyed on the 1/2 mill. map that only operate on a 28 day basis, ie. thereby not requiring planning permission. So some of the so-called zones shown on the map are not active for most of the time. how is a GA pilot, glider, micro, ballon or whatever supposed to know?
Wouldn't it be a better system if these part-time zones were activated by notam, in the same way as PJE's are notified when not associated with a designated drop site? I think the maps should also dispaly drop zones in red and not in blue.