Another hybrid quacker

I thought this was going to be a female Pochard x Tufted hybrid, but by pure chance I happened upon this post on Dominic Mitchells blog, with what look like two identical birds. Keith Vinicombe thinks his are Pochard x Ferruginous, albeit at the Pochard end of the spectrum. I actually suspect my bird is identical to his top bird, so maybe it moved to Stewartby Lake from Alexandra Park in London? Stewartby Lake, Beds, 8th January 2011.