I'm not sure if the tail is damaged or wet in Ivan's photos; an obvious question is whether all Raymond's photos were taken at the time of his original sighting and then Raymond's were taken later.
I'm not sure how significant the fact that the wax tips to the secondaries are irregular (i.e. not the same on both wings)is; but this is something we can check up on. Primaries are worn but perhaps not abnormally so for a first winter bird.
Overall, though, I think that as a single bird with some feather damage it might be difficult to demonstrate that it is definately not ex-captive.
Mike