This is a screen grab from the video below and shows many of the salient feature that separate this species from the very similar Marsh Tit: the wrap-around white cheeks, dull black crown and lack of pale base to the cutting edges of the mandibles as well as the very clear pale secondary panel.
More distinctive though is the call which is how I picked up the bird in the first place.
Willow Tit
Poecile montanus kleinschmidti
Canon Powershot SX50 HS