Thanks for pointing this out Darren, I mistakenly wrote leeks in the photo caption instead of spring onion, and have changed it. You are right, it is too late to plant leeks now unless you are happy with small, spring harvests.
Also in the blog I have posted about a sudden onslaught of leek moth, which must have been flying en masse in the earlier fine weather. Leeks I was harvesting today are quite damaged in their upper stems as the caterpillars burrow in, all since last week when they were fine. There is nothing one can do to prevent more damage once they are burrowing away, it is disheartening. I could have covered with enviromesh but prefer to look at my leeks and not too many white covers!