After how many years could you leave to pursue other ambitions and then hope to potentially regain your previous position?
You'd better keep that bit to yourself, you won't be employed in the first place. ASA keep a blacklist, if they don't like you or you've done something they don't like, it doesn't matter how short staffed they are, you won't get back in.
You'll need 5 years experience before an overseas ANSP will look at you.