Where to find Jerusalem artichoke?

[SummaLuvin]

I have a recipe I really want to try that uses Jerusalem artichokes (roasted Jerusalem artichoke and chickpea chaat, by Meera Sodha), I looked in my local Morrisons - normally good for fruit and veg, and they didn't have any, nor did it look like they had space on the shelf. Does anyone know where to find them?

I get an oddbox delivery of misshapen or glut fruit and veg and 2 weeks ago it had a kilo of Jerusalem artichoke in, so they are still in season somewhere!
(I sometimes substitute daikon radish for them for roasting, though it doesn't have nobbly skin so it less nutty, it is still a good dupe).

My allotment, they are in season.
PM me if you want to grow some yourself.

Sainsburys has them at the moment according to the grocery app.