Onion sets 2022

I've sown a row of senshyu seeds outdoors for the first time ever. They're popping up as we speak. Are they winter hardy? Never really had success with onions from seed, also never sown in autumn. What do I do next? I think the likelihood of neglect is on the cards. They'll need thinning I expect so I can hedge my bets and pot up the thinnings and keep them  undercover I suppose.

I've not grown that variety but all autumn sown onions are winter hardy. I've pricked mine out in to modules are they'll go in to the greenhouse border in October. The sets will go outside somewhere. Similar to garlic, they grow slowly over winter then in February as the days get longer they explode with growth. They will be healthier (as they won't get battered by storms etc.) and earlier to harvest undercover but it's not necessary.