Not quite sure what you mean by a "living allowance" but if you are given accommodation then that usually covers it. As you can see by the number of applicants, GES doesn't need to negotiate and if you are in your first year of teaching, I wouldn't bother, they won't budge. Don't sell yourself short, if it isn't at least 25% more than you are making now in the UK, don't go.
Mandi