I have heard quite a few allotment holders saying there Autumn sown onions have been going to seed! With this in mind I checked mine the other day and today and found four out of approximately 250 of my onions have seeded. The rest are bulbing up nicely.
Took a lump of strong chedder with me yesterday and had two of the seeded onions with it for my bait! Very tasty it was too!