I can confirm that when I broke the tip off one of the leaves it did have an oniony smell. I'm just trying to think now exactly which year it was when I tried to grow leeks (without success). It might have been 2011, What happened was when I sowed them I forgot to take into account the growth of the surrounding plants and they got swamped and then died from lack of light (or so I thought). Is it possible that a bunch of them could have struggled through and had their growing lifecycle extended?