I grew them from seed. Had them indoors for a while till they grew too
big and then put them in a cold frame. They had to put up with several
cold nights till 2 weeks ago (down to 2 or 3C), though I did cover them
with some fleece. I could see from the leaves that they had suffered
slightly from the cold, but now they all seem to be growing well. Maybe
it's the sudden temperature swing within the last weeks that's causing
the stress, and one of the plants is a wimp.
With the plants that had blossom end rot, I'm sure they were wilting
too. I seem to remember that the growing tips of a few of them just
shriveled up. Maybe they had blossom end rot and some other virus in
addition.