In case it helps anyone. Samut Prakan immigration (which is now located in the newly rennovated Pak Nam office) accepts the following documents for 60 day extension based on marriage/family.
Copies of the following all signed and notorised:
- marriage certificate (in case of wife)
- birth certificate (in case of dependant/child)
- tambien baan of wife/dependant
- ID card of wife/dependant
- all passport pages with ID and stamps
-TM 30 Receipt of notification copy (make sure it's date-stamped from when you last entered the country, they flagged this with me and I got a telling off for not reporting 24 hours within entering the country)
-1900 baht
-wife/child in person as they want to take pictures of you as a couple/family
-passport photo for one of the three forms you have to fill out
Not needed contrary to other reports/offices:
* Kor ror 22, you don't need any copy of this, whether it is old or newly updated.
TLDR : Answer Summary
To obtain a 60-day visa extension based on marriage or family in Samut Prakan, the following documents are required: a signed and notarized marriage certificate (if applying as a wife), birth certificate for dependents, 'tambien baan' of the wife or dependent, ID card of the wife or dependent, copies of all passport pages with ID and stamps, a TM30 receipt dated from the last entry, 1900 baht fee, a passport photo, and the presence of the wife or child for photographs. Some documents, such as the Kor Ror 22, are not needed contrary to other reports.
