With all the talk of drink on this thread,then why not try the 'Geordie' Leek growers' tip- give your Leeks a drink of 'Newcastle Broon Ale'.
Mind you-make sure that you filter it through your kidneys first!
Seriously though,I really think that they should have been well supplied with nitrogen in the summer,as I think that too much nitrogen now leads to weak plant tissue that isn't so good at handling cold weather (not that it's particularly cold at the moment).
As a native of Exhibition Leek growing country,I don't go in for shows,preferring to simply grow for the pot-so my leeks aren't anything to shout about either!