I wouldn’t recommend “a” bank, I would have several different bank accounts and at least one travel credit card which doesn’t charge a fee for foreign transactions. 
I’ve recently travelled from the UK to Bangkok. My passport was stamped 60 days. I understand from May 1, you have to fill in an online form before you travel.
you do realise many people in the UK over 50 ,who own their own house have a private or company pension and saved investments would be millionaires. I’m not planning to leave UK when I retire, but I do intend to spend the winter years in warmer climates. 
service charge on restaurant bills. You’ve obviously never travelled to the US Canada ,Oz most of Europe etc. Also what do you mean second most exodus of millionaires? Which country is the first most? Are your statements factual and evidence based or do you just make them up? I understand this is social media and people can just say what they want .