I-hang-about-in-doorways, just read the comments made by X-quork and ORAC.
Most certainly it is incorrect to obey an unlawful order - even in an aeroplane. I was once told of a Nimrod first pilot who, having overshot at Decision Height was exhorted to 'take it a bit lower next time' by the navigator captain.....THAT is an illegal order. (Fortunately he just got out of his seat and said to the stupid ar$e - "OK, all yours, you do it!". Then they diverted!).
NOT commenting on the forthcoming DCM but to say that the whole GW2 saga was greatly unpopular with much of the nation and I know many in the Armed Forces harboured doubts about the legaity of the whole thing - although of course they did as ordered. To take this to DCM seems a huge risk; if the Crown loses, what precedent will this set?