I've heard variations of that particular horror story, plus others, in various places (
http://www.thehighroad.org is one such place, if you can tolerate the occasional tinfoil-hattiness). [rhetorical question] How did we get so far upside-down and bass-ackwards to hammer the defender instead of the aggressor? [/rhetorical question]
Yeah, you'd need more than a few changes. There's a whole chapter of my state's penal code entitled
"General Principles of Justification" outlining in mind-numbing detail self-defense, defense of another, defense of property (sorry, the BG has to actually be burgling your house while you're in it, or doing a robbery or aggravated assault against you before you can pop him - not quite a "Make my day" law.
) Unfortunately, the last several years have erased a lot of the internalized knowledge of firearms in the UK, so you'd probably have to tack on an extended training requirement to your licensing (I'd suggest maybe a Saturday afternoon class each week for about ten to twelve weeks, with sat completion of tests and qualifications might be a good notional figure)
But the real key is a change of mindset. As long as the people in charge continue to think that you can't be trusted to protect yourself, they'll continue to deny you the right to do so (
vide your farmer). Something I firmly believe is that, at bottom, if the BGs are willing to ignore the laws against murder and mayhem, why would they stick at mere weapons bans? Weapons bans simply make easier victims for the BGs. Granted, the EU would have a conniption fit, but, frankly, I've never been so sure the EU was such a great idea anyway...
(And, at the risk of sounding like I should be trying on a tinfoil hat myself, I'd also point out to the people who fear a McBushitlerburton-type takeover that enough armed and mistrustful citizens can cause a would-be oligarch to give up the whole idea as a bad job - but, as stated, that's a bit tinfoil-hattish for my taste)