Looking at it, again it did have a bit of dead leaf at the main area... Top info guys Thankyou... I just learned a new lesson.Yep dead leaf is how I found it, i keep my eyes pealed now for it, but extra fan and a little Dehumidifier is the way to go mine was definitely down to airflow and it being the shortest plant in the tent in a corner.
I've decided to harvest all 3 plants today now just in case it happens to the other 2.
RSB