Thank you very much for confirming what seems a logical process

@Ellie ******

Thank for the clarification. So, it seems that for me that means a trip out of the country to either get another Tourist Visa, a visa exemption entry or a Non-O from an overseas embassy or consulate? Thanks again.

@Ellie ******

Just to confirm, my wife could apply for a 90 day non-O outside of Thailand once I have my 12 month extension, then she would go to an immigration office inside Thailand before her 90 days are up to get another 9 months extension? Then the following year we could both apply together in Thailand to extend our respective 12 month extensions? Thank you.

@James *******

UK (me) and Japan (wife). We can apply at out local consulate in Japan but the embassy/consulates in Japan tend to make it more difficult than SE Asia with extra documents and requirements, unfortunately.

@Ellie ******

Thank you very much, that is very helpful.

Yes, hence the idea we would apply together but it seems much easier for her to apply in Japan and myself in London, unless the London embassy will be flexible.

Indeed, there are but in that case I won't be able to fulfill the (strict) requirements. So, I have to apply from UK and wife from Japan? That could be an option but seems extreme.

I will have to call them but not just yet as things are only in the planning stage at the moment. Just exploring options at present. Plus the rules could change again anytime. TIT.

In this case my wife has only visited the UK for a weeks on holiday so hardly an illegal immigrant from a 3rd world country. Wonder if common sense would prevail...

Well, I will call them nearer the time and report back. Other embassies around the world make allowances for spouses but nothing is mentioned on UK embassies/consulates' websites.