Restricted zones on charts.
The Severn Estuary has three circled area's, I presume, that have fly over restrictions.
EGR 154 is a nuclear power station and EGR 155 a decommissioned one.
The next one, going inland, is twice as big, and joined to the other two.
It has the designation EGW SEVERN.
Without breaching the official secret's act, which I have signed, just what do the three letter ident's mean and why is EGW SEVERN seemingly restricted?