You’re 57 health insurance will only ever go up especially if you have any chronic conditions
This is just the way health insurance works as you age it goes up and up and up because the risk of coverage increases every year you’re alive, hence why it’s near impossible to get a private insurance after the age of 66
…the only way to offset it is to have another policy via a pension etc that will cover any chronic conditions which you can omit from the Thai insurance policy
I have found through my own trial and errors is that all the companies are intermingled with each other so by omitting something from company A won’t insulate you from company B finding out
You could opt for huge premiums in the range of ฿60k-฿100k to offset the cost
Look into Allianz or NOW insurance (out of HK)
The only cheaper insurance for you is unfortunately your UHC in the UK
In your 2 countries I’m guessing you’re a citizen and the rules are different for you as a citizen
I’m probably sure you don’t keep up with foreigner rules in the 2 countries you’re a citizen in as far as visa requirements businesses opportunities and tax requirements
So if you own property in Thailand as a foreigner to use as a Monthly investment stream via rental income you need to have a WP and TIN to do so
Thais are citizens in Thailand just like you are in your 2 countries and play by different rules than foreigners