Thanks Built.
I'm taking both your advice- letting it recover before flower.
I just pinched off all leaves, most just crumbled in my hands and the ones that still have some life in them I left alone. The tips crumbled off but i'm leaving the half leaves on them for the plant to figure out what it wants to do with them- kill them off slowly or try to keep them alive. I will remove them if they dry in a couple of days as you said..

I think water might have been an issue too. My mum was watering them, but just with a watering can, so no run off, not much water. I can imagine they dried out a bit. That and poor lighting are the only causes I can think off.

I bought a 400W HPS today. So excited! It's up and running. Quite warm, but it's an open closet for the heat to dissipate and there's a 6inch fan on it, so hopefully all is ok. Hand test seems fine. Well wishers who have followed my grow and have saved my plants from my non green thumbs, I can imagine you are happy for me and the HPS

Regarding nutes- I have biobizz (the green all mix). it's organic i believe...
I'm giving them the 1ml per litre like the instructions say, as they are full sized quite large plants by now.
I have the both of the recommended flowering bio bizz nutes available for when i get into flowering.

I will give you an update on the plants in 5 days when I can see how they are recovering with the light and good water again, but if you can think of any other reasons for the plants going mental, please do let me know!

Thanks for your help everyone!