Yellow Wagtail systematics is complicated to say the least! But some speculations over your Yellow Wagtail, which might not be the wholly thruth so to speak!
There´s a wide agreement that 'dombrowskii'-'xanthophrys' and 'superciliaris' are integrades - with 'superciliaris' and 'dombrowskii' coming from a wide area of intergradiation between feldegg and flava - 'superciliaris' probably also between feldegg and beema/feldegg and cinereocapilla, with 'xanthoprhys' being a rather rare intergrade between feldegg and lutea or feldegg and flava or beema.

The somehow greyish crown on your bird Domen might perhaps suggest type 'dombrowskii'(or something else), since 'superciliaris' usually has a black/ish crown.

type superciliaris

perhaps instead 'xanthophrys' over 'superciliaris' since supercilium is yellow and not white as in 'superciliaris.

JanJ