Onions from seed?

I've bought a packet of Bedfordshire Champion for next year. We've just turned the heating on in the house so I might sow a few now to see how they do. I've also got a few 'up-to-date' seeds that I'll sow as well. I didn't get these last seeds till late March and they did not grow very big at all. I'll try sowing earlier to see if they do any better. I've kept a few of the larger bulbs to plant out early next spring to see if they will produce some good seeds.

I had been hoping to save some seeds from some onions that kept very well from 2019 (sturon or stur bc don't know which as they came by post in paper bags that had split and mixed in the package) - but they are still flowering now so I doubt I'll get any seeds from them.