Hello,
I can understand that you presumable want/need a fast ID of a possible scarce bird (I learned here that White Wagtail is regular in some parts of the UK).
But I think, the original pictures are needed for confident ID here:
- please add location. No its not biasing in this rare case, I hope.
- the relevant rump area seems visible and true black. But it is yet-black, I think only judgeable on the originals,
- same with the exact shade of the upperparts. It may be well fit both White and Pied Wagtail,
- such a yellow shade to the face with a lemon touch is not very common in a White Wagtail. But yes, it (scarcely) exists and doesnt exclude a White Wagtail. But slightly better for a Pied? Err yes???
I hope this doesnt come out as an offense. But I hope its clear that the originals are needed (and why I am biased towards a Pied Wagtail, presuming its somewhere in the UK)