is it too late to sow more onions seed?

i thought id sown enough in april, but i hadnt,which ive now transplanted onto my plot. so i wondered is there a variety i can sow now to transplant after the early potatoes come out? My half full packet of ailsa craig says sow march/april, so i figure im too late for that  variety.
can anybody reccommend another variety?

thanks in advance

I've just resown some Bedfordshire Champion in modules to fill in some gaps in my onion bed.  They'll definitely not grow to full size but at least if I get some shallot sized ones I'll be happy.