Patrick Linden, you can apply at the Thai Embassy or consulate in the UK for the Single entry Non Immigrant O visa based on marriage which gives you 90 days on entry. Than after 60 days apply for 1 year Extension of Stay based on marriage but you need 400.000 Thb on own bank account in Thailand or 40.000 Thb monthly income certified by your Embassy. Or you can apply for the 1 year multiple Entry Non Immigrant O visa based on marriage which gives you 90 days on entry, make a border run to get another 90 days, if you make the last run just before or on the last until valid date of the visa you get 15 months out of this visa. Last period can be extended at local Immigration with another 60 days based on visiting your family. Than you have 17 months out of 1 visa. I answer here because this side loves to share information to all of the members in stead of private messages which can be sometimes not completely correct. On the side if information is not correct it will be corrected by the admins.
TLDR : Answer Summary
This discussion explains the options for obtaining a Non Immigrant O visa based on marriage in Thailand. It details the Single Entry and Multiple Entry variants, along with requirements such as financial thresholds for extensions. The post highlights strategies for maximizing stay duration through border runs and addresses community efforts to ensure accurate information.