I agree with Lesser Sand Plover - a juvenile of the 'atrifrons group'(sometimes split as Tibetan Sand Plover).
The strong ginger tones to the upperparts, head and breast seem to fit this best, as does the relatively weak bill.
There were quite good numbers of Tibetan Sand Plover when I was at Mai Po yesterday - I saw at least 18, probably more, and mostly juveniles.
I'm interested to get photos of any non-breeding (juvenile or winter) sandplovers, please PM me if you have any good photos.