Since the UK is a human construct, it's a bit of a reach to suggest that the creator of the thing is not native/indigenous to it. This is neither a theological matter, nor one of natural history.
Secondly, the idea of 'occupying an area for a period of time' is not a sufficient condition for a thing to ever be considered native.
The bee whose brooding, foraging, and storing characteristics are most evidently adapted to our soggy, foggy islands are native in a way that imports are not.
Regardless of higher yields and fewer stings, or how important and desirable those things may be to humans.
Mankind didn't "make" the island. However, if it pleases you to think we did, so be it.
Let me pose a scenario for you. I was born and grew up in the North-East of England. My parents and grandparents did too (I believe the statement holds true for several generations prior to that, but, we'll leave it at 3 generations). I now live in Bedfordshire where my 3 sons were born and have lived here all of their life.
Am I not native to the North-east, but, resident in Bedfordshire. What of my sons? Are they not native to Bedfordshire?
Words like this are merely labels to hang an idea on. The idea of belonging to a place, or originating from it. My sons are native to Bedfordshire while I am not.
The point is that if you're born in a place, you're a native of that place. In the same way, one of my carniolans that was born here, was mated / inseminated here and makes her colony here is native to here. She's not a native of some other place (i.e. Germany / The Netherlands) where her mother, grandmother or great grandmother came from because she has never even been there. In that sense, my carnica queens are every bit as native to the UK as those Amm that were imported from some other place.
If you mean to imply that Amm is more adapted to the conditions here, I would ask you to show me an Amm colony that performs like this (
https://www.beekeepingforum.co.uk/album.php?albumid=751&pictureid=3832). Is this not evidence of being suited to my local conditions? I think it is. My carnica performs better here than any of the local mongrels which, by your argument, should be better adapted.
These weasel words "native", "locally adapted", etc are really beginning to annoy me. They are loaded with an implied merit that the stock simply doesn't live up to. Beekeepers want gentle bees that don't sting the living daylights out of them, don't swarm excessively, are quite productive and are resistant to common pests and diseases. In a nutshell, that's it. They don't care about where a bees ancestors came from