Free depends on your age... if under 60 you're likely as you say get the Sino/AZ mix
I hung-out for the AZ double shot in my province, over 60
Otherwise it's see what hospital as what you want and pay for it.
Not sure if it would be an issue...
The original post says he traveled from UK to Thailand WITH wife & kids...
which means she resides in UK, could he get a visiting rights visa if she doesn't reside here?
just asking?
I don't think you should "convince" anyone to do anything where vaccines are concerned, it's a personal choice.
Supply unbiased information if needed but the choice should be theirs.