Anyone recognise this zipper? (RAF kit)

[John The Hat]

Does anyone have any info on this zipper ?

http://www.bysonleather.co.uk/Odds & Sods.htm

It is from an RAF flight overall (?)

Stores Ref A.M. 22C/775
Contract number 10508

I am trying to source a couple of sliders for a customer, but at a push a couple of zips would do. Not our usual line of business, but its a favor.

 

[Hawkeye]

It looks like the same type of no-name Air Ministry zips that are commonly found on late-war Irvin jackets. Theres been a couple theories here and over at Fedora Lounge about what the N (or Z) stands for, but i can't recall them at the moment.