Last season's leek crop

They all went woody in autumn. As I'm anxious to avoid it this year, I've been racking my brains to find a possible reason why.
First thought was the weather. Well we don't do heat-waves in N Cumbria so I doubt that was the cause. Neither was it particularly dry.
Same types of Leek as normal, Musselburgh and Lyon, so no clues there
Same time of planting as normal, germinated in March and planted out in May. So no clues there

Could it be the type of feed I used? Instead of the normal Growmore, I used some surplus high nitrogen pasture fertilizer. It seems unlikely to me as a cause but everything else was as normal.

Does anyone have an opinion?

I'll sow some more for planting out in July and see how they perform against the earlier ones. I may be wrong, but I'm sure that in the past I've always planted out in May. Maybe I've just been lucky with a combination of early plantings and poor summers. Last summer was the best we'd had for a few years so maybe that was the issue

Show leeks are the result of a long detailed process, which involves selected stock and very high levels of nutrients and additives to the soil, plus the use of grow-lights in winter. Unless you want to grow for show you really wouldn't want to go down that route 
http://www.giantveg.co.uk/index.php/en/grow-guides/11-growing-guides/126-how-to-grow-a-giant-leek

I'd work on getting more manure/compost into your soil and also use some blood fish and bone to keep them growing strongly.

I usually sow early, without problems.
What may make a difference is holding them too long in their planting trays or pots? It could be this growth check that causes woody stems/bolting.

I made the mistake of sowing a late Summer leek one year, hoping for a late winter crop, and while I fed and nurtured them all through the Summer, they looked terrible by Christmaz!

I tend to rely on lots of liquid manure (6X manure in a water butt and comfrey+nettles), and have vowed to water the ground not the veg this year as sometimes the blanched section is particularly streaked with brown...

Don't really like leeks until November, so we usually sow Bandit in various forms.

It seems to me that if you did something different last year, my suspicion would fall on that. If not, it's the weather. Too dry?

That's logical. The weather was quite normal for N Cumbria so I blame the use of high nitrogen pasture fertiliser instead of the usual balanced NPK Growmore. Won't make same mistake this year

Just checked the Bandit leeks, and there's about 150 up after living in the airing cupboard for a week, and so they're out in the greenhouse to toughen up, and start growing properly!

Still got about thirty from last year to give away...