Thanks to Graham Prole for the quick reply to say it was ringed by Irish Midlands Ringing Group as a pullus at Irelands Eye island colony off Dublin last summer 07/07/19. They ringed over 200 last year as part of a long term study looking at urban large gulls in Dublin.
The number is just a couple away from one that Brian S spotted in Pembroke Dock in January. Graham is appreciative of the sightings and said it is great to have so many fantastic colour ring readers in Wales. Keep looking!