They may be legal, and very tightly controlled, but it is not legal for you to use them inself defense otherwise why would a farmer be sitting in jail for defending himself. Why did they have to change the law to allow citizens to use bats and other weapons to defend themselves? Are all these stories bogus? Are you allowed to kill a criminal invading your house?
Also explain what you mean by shotguns and long arms being "tightly controlled". What does a person have to do in the UK to own a firearm ? Once you have a shotgun or long arm where can you store it, at home? Are you actually allowed to shoot someone who breaks into your house? I know you aren't allowed, I just want to see what you say.
"Tightly controlled" means being thoroughly vetted before being granted a license to own and the arms (type, calibre & s/nos) are recorded on the license and police records. You can keep them at home provided you have some sort of steel cabinet to put them in (similar to New York I believe according to the NRA website).
If they are for hunting, you will have to prove to the police that you have a place to hunt. For sport you will have to prove club membership (you get this after a 6 month probationary period) before you can apply.
Further,(my email crashes if my replies go over a certain length!) regarding self defence, "reasonable force" under the circumstances may be used - i.e matched to the threat - you can use anything really, as long as you can justify it to a jury. The farmer (you are referring to Tony Martin, right?) I believe was pissed off with being burgled, advertised his valuable possessions and set up an ambush - looking for trouble - shot the burglar running away. From what I've read (Massad Ayoob "In the gravest extreme/other articles), his treatment would be mirrored in your country.