Scorpii, from applying to getting the final 'congrats' email, took about five months when we did it.
Can't tell you if it's been the same each year, but mine went like this a few years back...
26th Nov - Registered
2nd Dec - Online application submitted
14th Dec - Invite to assessment day 1
Jan 14th - Assessment day 1
Feb 22nd - Invite to final assessment
Mar 25th - Final assessment
Apr 15th - Reply!
After this, you then also have to be around for things like medicals (one with the CAA or NATS, one at BA) and a family day (although perhaps not compulsory? Can't remember! Worthwhile, though.)