Waxwing (green over red)
Details were quickly emailed to the Grampian Ringing Group, who informed me that the bird had been ringed in Inverurie, Aberdeenshire on 27th November 2016 as a 3 male i.e. a bird born that year. My sighting was the first since ringing. Hopefully, it'll keep being reported again, either here in the UK, or possibly back as a breeding bird in northern Europe somewhere.
Other birds seen in the same tree were: Redwing (4), Blackbird (3), Bullfinch (1 female), Great Tit (1) and Mistle Thrush (1).