In regards to the Lesser White Fronted Goose, it has no clear signs of being an escapee and is apparently very wary of humans. Some have suggested it is from some Dutch reintroduction scheme. I suppose the scepticism of the bird being truly wild is the time of year it has turned up. See these two posts for more info - http://birdsoftheheath.blogspot.com/2019/04/lesser-white-fronted-goose-at-potter.html and http://birdsoftheheath.blogspot.com/2019/04/lesser-white-fronted-goose-black-kite.html