I started the D/L course in May06 and finished my last brush up and all assignments etc by the end of October 07 when I entered for the Jan 08 exams.
I met the requirements for completeing the course within 18 months which the school confirmed and when passing the final exams in Jan 08 (previous lot done in Jan07) finished the exams within 12 months.
Overall, just under 2 years from start to finish.
A friend who started at the same time as me has expired on the 18 months to finish the course and having passed 6 exams is about to lose them as he is coming up to the exams lapsing limit.