Ok, I'm 11dpo and just cracked and tested [embarrassed]. The test said to read the result in 2-3 mins. I couldn't see a line so was about to throw it away when I noticed a faint (coloured) line. It was after 3 mins, probably 5 mis so well within the 15 mins it said to discard it after.
I will test again in the morning but do you think it sounds promising considering period isn't due til the weekend and I didn't use fmu?