Wayne,ratting is a form of vermin control over here,referring to it as a sport is unfortunately very politically incorrect in the nanny state known as the UK
I have shot rats with an air rifle,using a lamp mounted on top of the scope at night when they have been causing a problem,it's all about having land or permission to shoot on private land,there is no shooting allowed on public land in this country.
Other pest species that are legal quarry for sub 12 ft lb air rifles include Rabbits,pigeon and corvids,but you have to be at close range,usually within 30 yards although it can be stretched to 40+ if you have a real steady rest.
I really like the new Weihrauch 97kt,a little on the heavy side but that makes it great for absorbing recoil,I can follow the flight of the .22 pellet to target which is impressive for a spring piston rifle,my other springer is a .177 that has been tuned but is still way to jumpy to do that.
My HW100 KT PCP rifle is almost like cheating in comparison to the springers,it literally places pellet on pellet out to 40 yds it can actually be a little boring to shoot.The modern scopes I have on the rifles are up to 16x magnification with adj objective lens that can focus pin sharp down to 10 yds and also have illuminated reticles,quite a contrast to the BSA meteors with 4x20 scopes I had as a kid