There are now 6 species in the Golden-spectacled complex, two occurring on the Indian subcontinent (Whistler's, Green-crowned - which, as Larry pointed out, has assumed the old name
burkii) and the other four occurring in China and/or N Indochina but wintering more widely (Grey-crowned, Bianchi's, Martens's and Alstrom's AKA Plain-tailed).
Green-crowned can be ruled out straight away, not only on distribution but also because it has a break at the rear of the rather weak eye-ring. Grey-crowned also has a break at the rear of the eye-ring and usually shows more grey below the lateral crown-stripe.
You would think, then, that it's one of the other Chinese species, but the bird definitely seems to have a break at the top left of its rather thick yellow eye-ring, although as modrawnu has pointed out, it seems less distinct in some images than others (are we quite sure all photos show the same individual?). Did the bird show this break in the field? This would suggest the Chinese race
intermedius of White-spectacled Warbler, which actually has a thick yellow eye-ring as on the OP bird, unlike the other two races. It also appears from the spread tail shots that there's too much white on R5 for Bianchi's and possibly some on R4 too, which would doubly rule it out, and I'm pretty sure rules out Marten's and Alstrom's. I am comparing the tail pattern, by the way, with the excellent images on a PowerPoint adapted from an Ibis article - it's too big to attach here, but click on this link:
https://www.yumpu.com/en/document/r...ctacled-warblers-a-complex-of-cryptic-species
By the way, putting these warblers in
Phylloscopus makes no sense to me.
I'm hoping John Allcock can chip in on this one.