Hmm Jemz I can see a line there! But the question is did you see it before 10 mins was up? I think after a certain time frame it has a bigger possibility of being an evap line, whereas if you saw the faint line within 10 mins (I think) it is probably positive!!
I guess test again tomorrow and see (well, that's what I'm doing!) and good luck, hope that line gets stronger in the next few days!