Alstrom's Warbler?

I think the following combination of features identifies this as Alstrom's Warbler:

    Unbroken eye-ring
    Black lateral crown stripes which only reach to above the eye
    Pale (rather than blue-grey median crown stripe
    Limited grey below lateral crown stripes
    Dull underparts
    Darker wash to sides of breast
    Very indistinct wing bars
    Very limited white in the outer tail feathers which does not inlcude a triangle of white extending towards the tail base

    Date is also good, with Altrom's being an early migrant (already migrating through Thailand in mid-Sept)