HI Emily. I had my stage 3 on the 8th and only found out i'd passed on monday (which was exactly 15 working days, due to the bank hol). I dont think i woldn found out that day unless i'd phoned up. so dont feel bad phoning, the first few times i phoned i had no luck just said they would get back to me but in that 15th working day i was actually phoned back about 10mins after my call.
When i spoke to the woman from HR i was told that she had been away for about 3 weeks and so things had been a bit delayed, i'd asked if they'd recieved my security questionnaire (as i posted it) and thats when she told me there was a lot of delays and things that hadn't been done due to her own and other abscene.
Just some reassurance, as i know i was going mad waiting for my result, especially as many others were finding out who had done stage 3 after me.
Good luck though!