This may not be all the info but as far as I know.. I had a spanish girlfriend at the time and she wanted to work in the UK. All she needed to do was apply for QTS (I actually did it for her online), and her teaching qualification was ?converted or transfered? into an English one, giving her QTS. No need for exta courses etc, was really easy and straight forward. Im assuming, it would be the same for an English teacher to go to spain. If you have the degree in teaching you simply apply for QTS and there you are.