Thanks man, great post.
Two questions, how much , in your estimation would you save to do that?
If you want to make it a bit challenging, you only need the money for a one way ticket and make the rest of the money there. I'd suggest take an additional Ł500 (or a plane ticket without specific date) to not completely jump into cold water and have some security for the start. But the less money you take with you, the more you are forced to deal with the new situation and be creative to make money there. You probably won't make the same jobs when you come back to the UK, but you will have new ideas on how to approach job searching which will massively help you finding something that is different from your old job.
If you are too scared of the unknown, you can take a couple of grand, but as I've said, the less you take, the more you will benefit in your search for a new job/way of living after you come back.
Also teaching English? I have A levels in English literature and English language (as well as a little bit of Uni learning) but wouldn't you need some fancy certificate to do that?
In Europe, a certificate would make it easier, as in most countries they already learn English at school, but you can probably still make a buck or two as a conversion partner for adults. After high school most people don't have many possibilities to speak English, but want to refine their speaking skills.
In South East Asia, I've met quite some people who weren't even native English speakers, but made their money for their time there as English teachers.