Well I am late with this post, the onions have slowed right down now, in fact they have probably stopped growing as I see no real swelling of the bulbs, I was expecting them to grow on until at least the end of August. my best bulb is 28.8 inches in circumference, I was hoping for 30 inch as that would have given me a 14lb bulb . Peter Glazebrook reports that last year in August his onions put on about 6/10ths of an inch a week till the end of August but I dont see mine doing that. 
My best bulb here is Ailsae, I have 8 originally and 8 of Peter Glazebrooks the only real difference I see with Peters is they are a taller bulb, Ailsae as in my picture here is more the traditional onion shape but to break world records one would need to grow it to about 33 inches in circumference.
