I have friend who has dual nationality (Thai/British), her Thai passport has expired so she it traveling on her UK passport to Thailand. She has booked flights to return beyond 30 days will she need a tourist visa or will her Thai ID be taken into consideration?
TLDR : Answer Summary
A dual national (Thai/British) traveling to Thailand on a UK passport can enter under the visa exemption rule for 30 days. If she plans to stay longer than 30 days, she can apply for an extension at the immigration office in Thailand, using her Thai ID and house book to secure a one-year extension for 1,900 baht.