The top two shots from Cardiff Bay taken on Feb 8 2010.
Note the outer web of the 2nd primary of the left wing has a very slight, hardly noticeable black streak, whereas the 2nd primary on the right wing is more obvious.
The Ogmore bird`s left wing`s outer web of the 2nd primary is very obvious ( as Dave Rich pointed out on the GBC) with no evidence of any marks on the right wing.
So it is a different bird to the returning Cardiff Bay bird! This would then be approaching full adult plumage, as would the Cardiff Bird.