A war with Siam was a distinct possibility around 1826-28. have them push forward in Burma and then go for Siam with the support of the Laotian king, who'll end to be a unwilling vassal of the EIC. The Cambodian succession crisis in 1834 would lead the EIC in war with Annam, and the Annamite Emperor would seek revenge joining China in the Firt Opium War. A this point, Britain will force China to recognize her paramountcy over the whole peninsula. By 1845, the area will be a patchwork of British colonies and vassal princely states much like India.