As suspected - N from BBA Glasgow's breezy response that it will be "absolutely fine" to take knitting needles on board was total nonsense.
Upon arrival at Glasgow Airport I caught sight of knitting needles on the 'not allowed' lists plastered all over the place.
I decided to be super-honest through fear of confiscation and spoke to the checkin girl. She immediately said no, and so I begged her to first look at my 2.25mm Brittany birch dpns first. When she saw them she smiled and phoned someone - saying 'no - they're like cocktail sticks and they're wood'.
And so I was cleared for knitting - although I had to check my metal crochet hook, metal stitch holder, scissors [obviously!] and weaving-in needle.
So the concensus seems to be bamboo/birch dpns that are very thin are OK. Anything metal, any straights (wood or metal) are not. Sock knitting it is!
I never bothered to mention them to anyone again, and knitted in airport waiting lounges and on the flight without comment from anyone - one girl stood watching me open mouthed for a while but that was all :)