Exactly. One of the most cringiest things possible is watching foreigners Wai at the wrong time and place. If you do not know how to do it correctly then do not do it was advice I have always been given. If you are meeting someone senior you will be given advice.
How does the bank know if I get a new passport? Absolute nonsense. Yes I need to update passport details at my banks but there is absolutely no way they would know if I did not tell them. Who woud tell them? The UK HMPO or Thai Immigration? The only 2 possible?
Anonymous participant 650 Certificate of Residence is the correct term. Often needed for a bank account. Needed for driving license and buying a vehicle among other things.
The travel between Singapore and Bangkok should be no issue. I often did it 10+ times a year on visa exempt when working in Singapore covering the region. .You will not need border runs or extension as you will get a new 180 days stamp each trip. If the trips are regular no need for 90 day reporting. TM30 re-reporting would depend on location - some offices want it after every trip while others do not bother if returning to same address.
Anonymous participant 406 I have been told I will have to do in person again after leaving and coming back - in Chiang Mai at least. My agent called her contact in immigration in CM to confirm. YMMV