LTN Phobia

That's a bit of an awkward one, although I would have been rather miffed at the selfishness of the group in refusing to wear a mask when everyone else was complying.

Unless it was a genuine mistake, to me, sitting in 1A when not assigned and being reluctant to move showed what kind of person she was - probably a selfish, potential abuser of her privileged position, taking it for granted that everyone else has to put up with whatever she does, which is something I find very hard to tolerate (I am a firm believer in privileges being accompanied by extra duties and obligations to do my best to do the right thing), so I would probably have liked to quietly address the matter in some ways, without making crew members' life harder (they are in a difficult position).

There is a limit to what crew members can do once they take off (a bit difficult to chuck them off), so I probably would have ended up shutting up and putting up, but probably quietly documented the whole thing, talked to the crew, recognised their difficult position, and with their cooperation wrote a complaint about passenger behaviour to BA, even though I would also assume that nothing would be done about it, and it amounts to nothing more than venting on my side.

I would not want the crew members to get into trouble with the company in any way, hence any complaint I submit will only be with crew members' cooperation, and if they had any concerns that they'd end up with issues, I'd even refrain from filing a complaint entirely, because I totally understand they've been put in a really difficult position and I have no intention of risking them being blamed. It would be the passengers I'm annoyed with, not the crew, and I don't want any comeback for the crew. However, if the airline would back them (crew) up, and my complaint triggers more support for the crew in enforcing mask wearing, then I'd be happy.

(My annoyance will not have been out of fear of catching Covid, but rather, that they were abusing their privileged position, basically.
Now, if I owned the airline and I were the captain, my response would have been entirely different! I'd have asked them twice, warned them once, and if no compliance, would have landed somewhere really obscure and chucked them off with pleasure, and sod the consequence.)