Spoke with the production manager at my place today, I'm quoting from memory here but basically only applies to new build and any foiled frame that leaves their premises complies with pas 24 or document q or whatever they choose to call it automatically due to all the reinforcing that goes into it, their basic C rated white windows wouldn't comply unless made to the same spec as a foiled window, locks and keeps and hinges already meet doc.
Surprisingly though if your supplier hasn't got the accreditation for say the PVC but has for his hardware I'm told he can get his frames made by a company that complies and then fits his own hardware kind of like cherry picking all the accredited parts from other suppliers and fabricating the completed article also piggybacking on others accreditation, seems a bit weird to me, he's had the BSI people in recently regards this so it was quite fresh in his mind, me........well he only told me 3 hours ago and I've forgotten 80% of it already.
Furthermore he says because it only applies to new builds or for planning submitted after October 2015 he can envisage problems quoting and whether to apply doc q to the windows or door or not, if a builder shopping for quotes doesn't spec then its the responsibility of the supplier to ask, if neither ask then your not quoting apples for apples, seems like a minefield to me