Interviewed on the 9th
Letter came yesterday(3rd) so approx 1 month between prelim and letter confirming their intention to have you to the third stage.
For you "Young" guys it will be quicker cause they want the whole thing wrapped up by early September
Incidentally re your point about Uni, although most people I talked to at the prelim were graduates there were some youngies there as well - from Eire - who had just finished their A-Level equivilents.
Good Luck WWW et al