I think that there are some slight yellow tones on vent, flank and rump. To meet it seems that this bird is a probably a hybrid in that there are some Rosy Minivet genes there but the hybridisation event was probably at least two generations ago i.e. most of its genes are Swinhoe's. If there are F1 hybrids (which would be classic 'stanfordi' then it is logical that there will also be backcrosses.
Regards
Mike Leven