I've had family staying with me for a couple of days and didn't get chance to do the flush yesterday as planned. The yellowing has spread to a couple more leaves and the plants aren't looking so good. I've flushed them and gave them 1ml per litre of bio bizz grow. They're sat in the bath now just drying out a bit before I put them back under the lights.

Any comments/advice? Anyone think I should be doing anything else or i've misdiagnosed nitrogen def/nute lockout?

Here's some pics.