Thanks Les. Yes I spoke to the consulate in Sydney and they said they definitely need to see the insurance valid for a year. So it looks like I'll have to do the same as you, cancel the existing policy and reapply for it again.

I called the consulate. They said the insurance definitely needs to be valid for a year. So it looks like I will need to cancel my current policy and sign up for it again.

Thanks Tod. That difference is exactly what i wanted to clarify

Thank you Tod. I'll contact the Sydney consulate and report back here what they say. If I end up getting another OA visa, do you know whether that would now be stamped in for the whole year, regardless of insurance validity?

I don't think any type of visa would actually permit him to work in Thailand under his present circumstances. But the profits from the company can be paid as dividends which is classed as passive income, same as the income from stocks and real estate. If you're in Thailand for more than half the year you have to pay tax on all money you bring in to the country, and passive income is not incompatible with the Elite visa or any other visa. It sounds like the OP is more concerned about the tax situation than the visa, so since this is a forum about visas it's probably best if the OP seeks tax advice in a different forum.

Your best option is to pay tax in thailand. Very low tax rate and foreign earnings are tax free if you don’t remit it into thailand

OK I didn't realise there is a risk the IO might refuse entry if I have a re-entry permit. Then it makes much more sense to come back on a visa exemption. I also didn't realise I'd have to cancel the current extension, I thought it's just automatically invalidated once you leave without a re-entry permit. Can the extension be cancelled while outside Thailand? If not, and if I hypothetically didn't cancel before I leave, would I have no way of entering Thailand until the extension expires on 14 December?

I've already spoken to the school, and while that may or may not be another issue for me to consider, it's not relevant to the specific question I have here.