Well done on the visa, but on a sour note, you've told the government you intend to live off rental income which means you supposed to file 2 tax returns each year if you stay 180 days or more instead of 1.you shouldn't actually owe any tax as you can credit off the tax paid in the UK as per the DTA.
Life will be a lot simpler if you sort it out before you leave, the 65k route to getting a visa isnt an option for UK passport holders. I'd at least get one while in the UK, and then you only have to worry about the spouse visa, which if you cant get in the uk, you can sort out here easier as you already have the visa to attach it to.
At a guess your UK passport holder, so you can only go the 800k per main visa holder to qualify for visa and first extension. To move to the 65k monthly method in the 2nd year, you need also to transfer 65k+ from 1st month of moving so you have to maintain both methods for the first 5 months. Then just 65k+ for the rest of the year to get yr 2 extension.
groups of people can meet and discuss issues, etc informally aka social gathering. But, the services i assume can be the physical output of the meeting, but i have no idea what services you had in mind. But running a play group, or after hours school group came to mind.
My belief is that if you keep these as social gatherings, then there is no need. If they become formalized, then legaly yes a WP is required. The requirement would probably more about the 'services', as these could be deemed as requiring WP especially if the provided 'sevice' displaces the need for a Thai worker.
Technically your tm30 'check in date' should always be greater than or equal to your tm47 'arrival date', to fulfil one of the 90 day reporting requirements.
because it has nothing to do with the visa, its a totally seperate law, and they didn't send you a document with the 1000's of other laws you have to adhere to either.