So long as you have an address in your home country all good. I don't therefore I can't plus I no longer have a home country sim card for contact, OTP, login etc.
Might be an idea to say what credit card you have and see if anyone has an issue if you wanted to change to a Thai address/mobile number for app/payment confirmation. I had 2 UK credit cards one is happy for me to use an overseas add/number, the other shut my account.
You mean no showers in toilets only bidets/bum gun?
They want a shower as they have a long transit time and are traveling to get to the airport and then the flights to the UK are long ones with another transit...