Same subspecies but evolved differently, what is left of them, mostly European genetics from the study they did and some pockets of native Irish bees, their DNA is different to the mainland UK and European subspecies, not a lot but different, if you consider the difference in dna between a pig and a human is 2% a small change makes a large difference.
It's also hard to tell due to the huge amounts of imported AMM bees during the last century and the lack of survivor colonies after IOW.
The constant waffle about black bees grinds my gears, they weren't black in central England they were brown similar to the ones found in the south west. Dark bees not black bees.
A few years ago as a member of BIBBA we were told BIBBA doesn't supply queens get them from x, which were not in mainland UK they actively encouraged the importation of foreign AMM stock to replace the locally adapted stock they had, even beowolfs bees were requeened with foreign AMM. Granted they had swarmed a lot and gone to pot after his death.
The whole thing has been transformed from a group of like minded individuals promoting the benefits/conservation of native bees to what is now a political lobbying movement with members infiltrating positions of power in a multitude of beekeeping organisations/fora to effectively silence opinions opposed to their beliefs. Absolutely crazy.