As I understand it, all ATr crews will hold military rank albeit as reservists for when they fly military sorties. I cannot see a civilian company selecting civilian pilots to be awarded with Queens Commissions, so I would have thought that the caveat would be you must be an ex QSP to qualify. Just a guess though.
If not, then I'd imagine they would have to at least do the tarts and vicars course at IOT. I guess they have already thought of all this though. Like they did with DAS and FTI......