The Law states
It is also against the law, in England and Wales, to fire an air rifle within 50 feet of the centre of a highway (which consists of or comprises a carriageway)if in consequence a user of the highway is injured, interrupted or endangered. These offences could be committed, for example, when someone is shooting in their garden close to a public highway and the pellets ricochet onto the highway.
So as long you are 15 m away when you take your shot you should be ok
yes 50 feet I was thinking 50m for some reason my mistake .... but I still feel the shots were irresponsible