@Barry *******
. . there never was a one-year multi entry Non-Imm-O visa based on support for a half Thai child. You only could obtain a 90-days single entry visa type on the Thai embassy in your country for this reason. Immigration, though, would issue a multi entry 1-year Extension of Stay Permit (not a visa!) based on raising a half Thai child. That's what you had. You didn't have a "visa", you had an extended 1-year stay permit, for which you had bought a multi entry permit. You can repeat just the same - get the single entry Non-O "family" visa based on support of a half Thai child, and change it into a one year Extension of Stay inside Thailand