I haven't applied yet but as far as I've been told there are interviews every month and courses every other month.
Word on the street is that a guy interviewing now would join after the summer (maybe September-October?).
I've also heared that for the guys flying regional or "small" jets they are doing now this pre-selection in the UK, not applying that to the guys already flying wide body and some of the well known narrow body (320, 737). Not sure if this is true, just been told by a colleague.
If that is your case, I'll assume that interviews in UK aren't running that often if compared with those in Japan.
Only talking rumors here, don't trust any word