Two of your cases would have had similar results in a lot of jusridictions (and I can't find much on the third)
JoergS said:
In 1987, two men assaulted Eric Butler, a 56-year-old British Petroleum executive, in a London subway car, trying to strangle him and smashing his head against the door. No one came to his aid. He later testified, ''My air supply was being cut off, my eyes became blurred, and I feared for my life.'' In desperation he unsheathed an ornamental sword blade in his walking stick and slashed at one of his attackers, stabbing the man in the stomach. The assailants were charged with wounding. Butler was tried and convicted of carrying an offensive weapon.
Possession of a sword stick is illegal and will get you jail time all over the world (including much of the US), had he used a cane/stick to beat the attacker he would probably have been ok, though the London bobbies are big on "reasonable force", when the bad guy falls to the floor, stop hitting him.
In August 1999, Tony Martin, a 55-year-old Norfolk farmer living alone in a shabby farmhouse, awakened to the sound of breaking glass as two professional burglars burst into his home. He had been robbed six times before but, like 70 percent of rural English villages, his had no police presence. He sneaked downstairs with a shotgun and shot at the intruders. Martin received life in prison for killing one burglar, 10 years for wounding the second, and 12 months for having an illegal shotgun.
He hadn't been robbed, he had been burgled. His problem was that the prosecution showed he hid out and waited for the burglars with an illegal pump action shotgun (only single shot/double barrel shotguns can be licenced amd possessed in the UK). When the burglars arrived, he chased them and then fatally shot the 15 year old in the back and the other in the leg as they tried to run away. Hardly a self defence scenario.
In 1994, an English homeowner, armed with a toy gun, managed to detain two burglars who had broken into his house, while he called the police. When the officers arrived they arrested the homeowner for using an imitation gun to put someone in fear. Parliament is now considering making imitation guns illegal."
couldn't find any info on this one.
UK law is simple, you can't be in public and carry an item for the purpose of self defence, you can, however, use anything to hand (with the reasonable test) if you are attacked. So a walking stick, umbrella etc is fine. In the woods, chances are even an knife would probably be ok. There was a recent case where a homeowner stabbed a burglar to death in his kitchen (so knife to hand) when the burglar attacked him and he was not prosecuted for the death.
As long as your actions are reasonable (to a normal MOP) odds are you won't have a problem.
For defence, (though NEVER admit to it being for defence) would be a good strong walking stick. Anyone can use one unless you look like the type to attract police attention (hint, gang banger or similar looking youth would probably get pulled).