Things seem to be much happier in the tent this week. I added a circulation fan which seems to have dramatically helped. Within 24 hours of adding it my plants were flourishing. I didn't think I needed one as my extraction is extremely overpowered. Another thing which makes me believe the circulation fan is what's making the difference is I have developed 2 runts on the right hand side of the tank. They aren't horrendous but they are noticeably smaller than the plants on the opposite side which are in the fans direction.
I have now put in place the dripper system and filled the tank to 1.4 ec. Come Tuesday morning I checked the tank and it had risen to EC 2.0, I have readjusted to 1.0 and will see how it goes.