I have had a .22rf now for many years - it is an old BRNO Mod 2 that has been extensively customised with a full size stock so that it handles like a stalking rifle.
It is accurate enough and I know it well enough that I am confident taking rabbits our to 70 / 80 yards using eley high velocity ammo.
And of course with subsonics it is very quiet - good for shorter range rabbits and for practice.
Mostly I use it for informal plinking and the beauty is that ammo is cheap - 50 rounds for under £5 - depending on what you buy.
I am interested in views on the 17 HMR or the 17 Mach 2 rimfires. Obviously flatter shooting than a .22rf and thus you do have a bit more range - out to 120 / 150 yds, but does a .17 replace the .22rf in your gun cabinet, or should it be viewed as an addition?
Also how the police view them on a certificate - is it an either / or or generally are they happy for you to have both?