There were two unusual-looking geese among the Canada Geese seen from the Domen Las Hide at Ynys-hir yesterday. The first I assumed to be a Canada Goose/Greylag Goose hybrid. The second was more interesting. After a bit of delving on the internet, I think it was an escapee Swan Goose. If someone else sees it, I'd welcome a second opinion.
(Note: Having subsequently seen a couple of captive Swan Geese at Llanelli Wetlands, I can confirm that this was a Swan Goose.)