Honestly, I don't mean to be harsh but I wouldn't bank on it.
If you've done stage 3 or maybe stage 2 then you might get a course in the next year, maybe 2
If you've just don't the initial tests its going to be a long time - basically until the market picks up, NATS start winning contracts or the next wave of retirees happens.
The fact is NATS have too many ATCOs as it is