with due respect eagle owl,, if any bird is bred in the wild , in Britain, is classed as a British bird, so im afraid your first paragraph is wrong [this is stated by the rspb]
again with due respect your second paragraph is saying they are native to Britain
once more with due respect , although these birds have lived in the wild in Britain,,for a number of years now,, how many reports are on record as to eagle owls attacking babies , humans etc compared to other large type birds ,, you would know the eagle owl comes out at night,[like all owls ], nests in the most remotest of spots, same as peregrines, and without meaning to sound arrogant,, i couldnt see many people taking their pram and baby through a cliff faced quarry in the dark,, i understand your feelings on releasing captive birds ,[these birds can be tame and unafraid of humans] , but wild eagle owls are in fact like many British birds , actually frightened of humans, as they probably know man is their only enemy [as you say] [somewhere on the photos column on pb you will see a pic of me with a tame eagle owl on my arm ], but can understand your feelings on the release of tame birds