speckledbob,
Was it a ‘copper’ that you spoke with or a call handler on the main switchboard (not that the service you should receive should be any different)?
Some air weapons are deemed more dangerous than others and are subject to stricter controls. It depends on the kinetic energy of the ‘missile’ they discharge.
The lad that fired the air-rifle could feasibly commit a number of offences under different acts.
I think the best course of action would be to visit the West Yorkshire Police website and Email the local NPT, flagging the incident – requesting they pay passing attention to the area and stop and Q any youths in possession of such weapons, dispensing words of advice where necessary.
Anti-social behaviour is a policing priority for many forces, as set by their respective Chiefs & PCC’s and thus incidents of this nature are progressed with a little more application then may have been the case in the past.