Luck you. In the U.K. it's strictly bare hands irrespective of what the vermin have. I had a nasty little encounter with 3 gentlemen of the ethnic minority persuasion about 4 years ago. One of them pulled a gun on me. May have been real or may have been a blank firer. Made the lethal mistake of coming within hands reach of me. Wound up as 3-0 in my favour. No, I didn't kill him - before you ask. They ran away after they discovered how dangerous someone who thinks that he is dead either way and has no intention of crossing the Styx alone is.
Having said that I would prefer a .22 Ruger semi-automatic pistol for pot an point defence. 2-5 rounds, Double tap to the center of mass followed by 2 aimed rounds to the head will settle matters. Just remember to wait until you cannot see daylight either side of him.......