it is impossible to be certain based on the underside alone.
The two were basically the continental & Sundanian representatives of a single species.
When Malaya (part of Sundaland) joined the mainland E. eyndhovii moves north into peninsular Thailand & E. doubledayi south into the northern half of Malaya.
As Yala is part of Sundaland it is probable E. eyndhovii is the commoner there.
E. eyndhovii; smaller ofteb rather so, FW male blackish brown, female upperside FW unspotted. HW central spots usually many ,variable.
Singapore have only E eyndhovii. http://butterflycircle.blogspot.my/2...mber-2016.html