This is sheer incompetence on the legal defense of Hastings. First you need to engage the enemy front or back to keep the advantage in combat. Never let your enemy get the advantage of higher ground or cover. If Williams was truly fleeing, he would have not been stabbed; he would have been running away and out of reach. Second, Williams had a crowbar in hand. As a club, a crowbar has the advantage of reach over a knife. Anyone with training in the use of martial arts sticks would likely prefer to use a crowbar over a knife.
I’ll bet the Old Bailey judge packs a hand gun for his protection.
There's a huge difference between the two. In hand-to-hand combat it's pretty hard to stab someone facing you when they are armed with a crowbar (or even another knife). Each of you will probably get hurt and if you're more skilled you may win, but you'll probably still go to the hospital.
But I guess this judge thinks it's cowardly to stab someone that is armed with a crowbar in the back just to protect your family and property. Oh well, just one more place I won't ever visit.