It all boils down to what 12 ordinary men and women find to be reasonable, having heard all the evidence. Many years ago, when I was involved in crime, I acted for members of The National Association of Licensed House Victualler (my favourite trade union, I loved the site inspections) and regularly found myself defending a licensee who'd used force to evict a troublesome customer. It always hinged on whether my client went too far. I only ever lost one case.
In Martin's case the evidence was that he lay in wait, and used potentially lethal force. The jury agreed. From what I read of the case, I believe they were absolutely right.
If you start thinking that your bees, or your DVD player, is worth a man's life, then you should go and live in that state in the USA where a householder thought it reasonable to shoot and kill a lost tourist who knocked on the door hoping to ask directions. I'm happy to live in a country that seeks to find a balance, even if I don't always agree with it.