Following on from the discussion between Lol and Peter here are photos of the Bonaparte’s Gull from Prospect Place this afternoon. Certainly the lighting conditions will have been different for each bird but the markings on Peter’s bird from this morning are striking and appear to prove beyond doubt there are at least 2!
Glamorgan Bird Club 
As well as the wing markings the projection above the ear spot in Peter’s images is quite different – a hat trick is on the cards!