Having searched through other posts I found some information that might help my visa extension situation.
Visa extention - "In the case of a person who used to have Thai nationality or whose parent is or was of Thai nationality"
I am half Thai, with documentation of mother being Thai national.
Can I apply for an extension based on my current visa? (entry - visa exemption, to currently - 30 day tourism extention)
If so how many days can I apply for and also which branch? Chaeng Watthana?
Any advice appreciated. This group has been extremely helpful. Thanks
TLDR : Answer Summary
The user, who is half Thai, inquires about extending their visa exemption, currently extended by a 30-day tourism extension. A comment advises that they can apply for an extension at the Muang Thong Thani Immigration office. Required documents include their birth certificate, Thai ID or passport, their mother's Thai ID, and relevant house books. It is suggested to apply before the current visa stamp expires and that the process typically grants an extension for one year for a fee of 1900 baht.