Interestingly, a possible cinereocapilla (Ashy Headed) yellow wag was seen at Otterhampton Marsh on Steart today (ref @WWTSteart on Twitter).
There is a male Channel Wagtail in rough grazing next to Pitt Bridge on West Moor, Hambridge.
I initially thought it was a Blue-headed Wagtail but the powder-blue head, the large white supercilium and extensive white on the throat makes it more likely to be the former. The photo on Twitter is poor but I have recorded this hybrid on West Moor before, in 2010, when I took better photos: https://goo.gl/photos/WLWf6ysvYZ97r6JH7 These show the white in the throat more clearly.
More information on this complex group and on Channel Wagtail can be seen here: https://www.birdguides.com/webzine/article.asp?a=2058