They changed the law so kids can't leagaly carry a rifle now unless supervised I dont think if I remember right it used to be 14 and then 17 to buy pellets now 18 My memorys not the best though.
I walked into them a few times with rifle over me shoulder no problems, good luck I'm stuck on a job watching a supposedly a pro pest controller just missed a 30yard feral and hes using pointed pellets ffs.
My mate has a French bulldog and it's forever under the feet and farts for England. Know a couple of lads with/had borders they can live a fair while mates lived till it was well over 17 another other mate got one 13 that still catches the odd rat and rabbit around his yard.