So the killie tank now houses the 3 males - a big difference in the tank environment now, each fish chases the next one smaller than it, the smallest has become a master of disguise by losing his colour and blending in with the driftwood. Makes feeding a bit harder as I can't see him, but I find some carefully placed bloodworms have disappeared when I go past the tank again.
Plants are doing well, all the crypts are regrowing and I have counted at least 20 of them.