Great advice, great choice. But definitely, the office at Muang Thong Thani has been closed down and the service moved on 18.4.2022 toChaeng Wattana. The service on the 3. floor moved to an office nearby on Chaeng Wattana, but that was for extending visa or such. You can still look that up on the Immi website, though the locations have not been updated on the website. I was out at Muang Thong Thani recently and there were notes all over the place to inform everybody.
Mick Mckee, I would advise you to go and talk to an agent, who routinely process visa issues. BUT compare prices for their service, as these prices vary a lot!
That is right, take the test, which is also available in English language. Else you would have to have an International Driving Licence from your home country. But really, the test is the smoothest alternative.
Voluntary membership in the SSO is possible for people, who left a company or stopped working. According to § 39 of the SSO Act one has to apply for voluntary extension within 3 (or 6?) months after leavng the last regular job. SSO will only stop, when one hasn't paid dues for 3 months or ones death.