I recommend Tod Daniels "Visa Advice" in Facebook.
in need of visa advice to a Facebook group called ' Thai Visa Advice ' and in particular, a guy called Tod Daniels who is a Moderator within that group
I’ll be arriving on a 90 days non o imm visa and want to know if I can extend this for a further 30 days at immigration. I do not need any longer, just a 30 days extension.