There is no link between NI contributions and NHS treatment. It is a residence based system. The NI contributions only decide how much state pension you have.
You get an annual extension, so 12 months at the end of the 3 months then 12 months annually from there. You need to have the stated cash in a Thai bank account (or use an agent). You can get a Multiple Reentry permit which allows you to come and go when you like during the 12 months.
There are different ways of doing it but I would suggest you each get a Non O on the basis of being over 50 from the Embassy in London before you travel. You apply online and you get an e-visa.
This will give you 90 days on arrival in Thailand.
If you’re not sure about accommodation just book hotel or short stay in condo to look around. Don’t commit to long term rent until you’ve tried different areas/buildings.
You can open a bank account each when you arrive. They’ve got more strict so you might need to use an agent just to get your accounts. It should cost just under 4000 baht each.
You’ll need to transfer at least
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0 baht into each account in order to get your annual extension of stay.
It needs to stay above 800k for 3 months afterwards and can’t drop below 400k thereafter. It needs to be back up to 800k at least 2 months before the following year’s extension.
It might be easier just to leave the 800k in each account.
You’d have to leave the country after the initial visa ended to ‘kill it’. You then have to start again with a Non O. It is possible to enter on a Tourist Visa, or even on Visa Exempt, and then convert to a Non O in Thailand but it can be a bit of a hassle. If you’re sure you are retiring to Thailand then IMHO it’s best just to start with the Non O. It’s not difficult to get the annual extensions. That’s assuming you have 800k baht each to put in a Thai bank account and leave there. If you start with a Non O-A and just want to stay then you need health insurance with a Thai company each time and it’s not worth it.
As you are over 50 and want to stay a year then probably best to apply for a Non O-A visa from the Thai Embassy in London. It’s all online now. It does require a police check, a medical form and health insurance but you’ll get a year on entry.
If you think you might want to stay more than a year then the Non O ‘for Retirement’ might be better BUT you’ll need to have
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0 baht in a Thai bank account for you to get a year Extension after the initial 90 days the visa gives you.
There are some agents that advertise condo purchase this way. From what I’ve seen, most tend to be in buildings where it’s more difficult to sell and all have an asking price significantly above open market prices. I guess this is the ‘interest rate’ but impossible to calculate without detailed knowledge of actual recent selling prices for normal cash sales.
If the IO spoke to you last time it is very likely they will at least question you this time. Yes, having the cash, looking presentable, having a flight out of Thailand within 30 days will help but there’s no way of knowing how strict they’ll be. There must be at least a chance they’ll send you back to Singapore but they may just give you a hard time. It’s also possible they’ll say nothing.
I had a look at the Thai Embassy website and it says to allow at least 21 days when applying for a Tourist Visa. You complete an online application which is checked and then they give you an appointment. Return flight, hotel bookings for your entire stay, minimum 1000 SGD in a bank for 2 months.
From what you said, you won’t have time to get the visa anyway so up to you whether to risk it.
My guess is they’ll let you in but you can’t be certain.