I don't disagree with your point, except that I'm not exactly trying to appease here (I guess it sounded that way though) - I actually think both points of view have merit which is why I'd go with the Anglo-Australian type of construction (and maybe drop the Manx in the first sentence). As I said, if you had asked me before this discussion started where the Bee Gees were from, I would have said Australia, based on how I recall them being promoted in the 60s, and I also totally see the logic of considering them English so the dual wording does make sense to me.   I've looked a bit and haven't come up with anything on the web to answer that question yet - maybe you'll have more luck.   

By the way, Olivia Newton-John may be relevant here:  she is considered Australian as well, and her WIki article calls her "English-born Australian" or words to that effect.  Her bio says she was born in England, moved to Australia at age 5 and moved back to England at 16 where she began recording - a pretty similar story to the BeeGees, and she's listed as Australian which might be how she self-identifies, I don't know.  But on a quick read it appears she only lived there for about 10 years, like them.

As for whether this editing is personal, I have no idea and don't want to get into it.  I do know that I  am trying to reach consensus among different points of view, on this exceedingly minor point - and as I have said, there was some fussing about it a couple of months ago and it settled down with the awkward wording, because it is accurate.  So I hope we can drop this quickly and move on to something more substantive.