SirToppers,
I think you're right about Substitution Pay - the "as well as" factor is the key.
However, I'd be very surprised if any of these 3 particular individuals will have "brought this up officially" in the sense that I think you mean. I don't believe they'll feel they've been put upon; indeed I think they'll be taking this on very willingly, so I don't think they'll be registering complaints. I'm equally certain that their Sqn bosses and Stn Cdrs will all have tried everything they can think of to get them some reward. The bureaucracy just isn't flexible enough to allow such recognition.
P.S. Antipodean Charlie - they're talking about lunch over on the Formation Flying thread - I assume that's still one of your few specialities
