Incredible, aren't they? But don't worry, normal folk - those are 'pot' leeks?? And for cooking, I'd rather have the slimliners. If you've got plenty, use them finger-thick, especially King Richard, to add to dishes.
And keeping? See my 'Early winter veg' comment. Should depend on variety & planting date. Our usual time is July but, this year, these went in late May. Fortunately, we do have a back-up. = Tim