Interloper Goose with grey lags?

On my last visit to RSPB Conwy (see: RSPB Conwy 21 Sept 2019) I had observed an "interloper goose", using Dave CH's words, who commented on it, that had flown in with a flock of grey lag geese.

I would guess others will have noticed it as well.

After some searching, and various suggestions, I'm tempted to think it is a Canada goose with non-standard markings, or possibly hybrid?

I'm open to any suggestions...