A select few? Shotgun certificates are easy to obtain. My shooting neighbours grumble about the paperwork, but none have any difficulty in renewing. There could well be more legally-owned shotguns and hunting rifles in circulation now than at any time, given the booming popularity of country shooting sports. (I have two large commercial game shooting estates within hearing distance of my house). No problems with storing them at home, as long as you have a secure gun safe.
Shotguns and sporting rifles have always been by far the most widely-owned categories of gun in Britain, and have scarcely been affected by the various gun control measures. Handguns were always a very small, fringe interest by comparison.
Also, what would happen if an intruder armed with a knife broke into your home and you shot him to death?
Third, you mention "sporting rifle." What constitutes a "sporting rifle?"