Continuing slightly off topic, the following might be helpful.
"To fire a bullet or shot onto land that you have no right to shoot into or over is ‘constructive trespass’. Whilst this is a civil matter BASC strongly advises not to do this."
"Please note that in the case of air weapons it is a criminal offence to fire an air pellet outside the boundary of your permitted premises."
"If you shoot from a path situated on somebody else’s land (regardless of who owns the rights to shoot on the land you are shooting into) it is taken to be armed trespass which is a criminal offence."
"?It is an offence to enter any building, part of a building or land (including land covered by water) with a firearm without reasonable excuse (the proof whereof lies on the person). [Section 20 Firearms Act 1968]"
Taken from
https://basc.org.uk/wp-content/plugins/download.../download.php?id=49A photo or video from your phone and a word with the local firearms officer if they persist?
Magnus