Which variety of cauliflower is it? There are summer, fall, and winter bearing types.

Cauliflowers are not the easiest of plants to get to flower (i.e. produce a curd) they need very heavy feeding and even then we've found that no matter what we do we don't get the big heads that the commercial growers do.

I once had an allotment where I planted some caulis. The allotment next to me also planted a row and then because of family problems neglected the plot through the entire summer. His caulis were hugely successful, peeping up among the couch grass. Mine were practically useless.
Doesn't answer your question but I'm reaching the age for reminiscence...

From the Cauliflower page of the Vegetable Garden Guide:

"Sow summer varieties of cauliflower under glass in mid January and transplant outdoors in late March for a crop in June/July. Sow outdoors in early April and transplant in June for a crop in August/September.
Sow autumn varieties of cauliflower outdoors between mid April and mid May transplanting them in late June.
Sow winter varieties of cauliflower in May for transplanting in late July. In the UK growing cauliflower in winter is usually only successful in the south/west - Devon and Cornwall especially. For more northerly areas it will always be a risk."

http://www.vegetable-garden-guide.com/how-to-grow-cauliflower.html