Thats really interesting to read as I've had problems in the past with my plants burning when they start to get close to my led's - usually at 15cm away. Up until that height the plants are brilliant, grew like nothing else. At first I was thinking that you can't burn plants with led's and assumed it was me overfeeding, but no I came to realise that it was the lights being too close and that I couldn't in fact have them as close as what I'd read.
What you've written confirms I did the right thing by backing them off. Thanks for that