So yeah here we are at week 3, unfortunately as I mentioned before I had to transplant them for a second time and by doing so a plant's soil body ripped itself into two, probably causing root damage which you can clearly see the plant is suffering with. So I decided to plant a 4th plant immediately after that to cover for the loss and germinating it with a paper towel and then putting it right into the 12L pot instead of transplanting!
Still using pre-fertilised 8 months potting soil, NPK being 12-5-10, so not feeding them. Not sure if it is going to work but let's see!