Im not 100% certain and Im sure someone will come along and tell you, but I thought it was 50ft or 17yards from any public area, and in no case must you cause stress or alarm, I also think your pellet must not cross a public path/highway.
I try to be as hidden as I can in a few of my perms, on one which is a large livery stables with 150 horses and owners all over it, I carry my rifle now in a fishing holdall and they wave and say hello, I started there in a slip they scowled and pointed. So now they think im going fishing in lake as I walk from carparks, which keeps the farmer happy as they have stopped calling him, and he then has to explain Im allowed!!!
Regards
Chris
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