Morning David.
Glad to see that you are getting stuck in!
It has always amazed how volunteer groups and colleges provide their students with the most ill made, ill fitting tool - the Bulldog hook. I amazed at how anyone sticks to 'rural skills' after they have been using one of these completely ridiculous tools, tutors should know better, shouldn't they? The tools that you use are all part of the skill that you are trying to learn. No one will ever be able to call themselves a hedge layer until they understand and have mastered their tools, there is no compromise.
With regards the mitts, it is a case of hand protection. In the main, when you are laying a broad leave hedge you don't really need a mitts or gloves but when you it comes to the thorns then this is a different matter. I would dream of tackling a blackthorn hedge without some serious hand protection. Blackthorn has a serious habit of infecting you if you 'thorn yourself' I still have black stain under the skin of my left hand when a thorn had me back in the early 90's when I was dropping a hedge................I couldn't work for a week as my hand had swollen up like a balloon as blackthorn will poison you, badly - do not take any risks with it.
The reason mitts are superior then gloves is basically that you don't not have any weak points i.e. the seams. You will drive a thorn down between your fingers with out even knowing it, seen this happen many many times. The thorn group are so called as they have thorns, they have thorns as a self defense mechanism, not much in the animal kingdom will tackle will tackle them.............until us soft skin humans come along believing that we are tougher than anything else.
Working a hedge all day long is serious graft and you need to be in the best comfort that you can so you don't become exhausted as this is when accidents happen and as you can imagine, hooks do not usually take prisoners. Gloves are fine but over the day they soon become uncomfortable as they start to rub especially when you are pushing the hedge down by hand.
Hope that helps, if not then please give me a shout.
Best wishes.
Jack.