Given that you are both Canadian.. I'm assuming that you were not married in Thailand.. and unless you have done this already I'd suggest you obtain a translated copy of your marriage certificate.. meaning from English into Thai.. before you travel to Thailand.. this is likely to be needed at some stage of your future dealings with the Thai authorities.. and will probably be less costly to acquire in your home country.. it also removes the inconvenience of trying to get it done here.. especially if you suddenly need to produce it quickly.. just a thought!
Why does your bank need to know you are no longer intending to be a 'tax resident' of the UK.. you should change your correspondence address to your son's / daughter's address in the UK (with their permission of course) in order to give yourself an official or 'bone-fide' address for all your UK business.. then you get on with your life.. you can even maintain your UK mobile number by transferring it to a low cost expat telephony service.. so you will still be contactable on the same number.. and nobody needs to know where you choose to sleep at night ;)
Singapore also imposes certification of tax clearance before a foreigner can leave the country.. if your employment pass (or other work permit) is cancelled you cannot travel if there is an outstanding tax liability.. your passport is blocked by immigration!
If you are a mature guy looking for a serious relationship with a 'wholesome' Thai girl / woman.. and are looking for a long term partner / wife.. rather than a good-time girl who doesn't share your aspirations.. then I'd advise batchelor boys to expand their social circle.. and focus on friending expat guys who are in longstanding marriages to Thai women.. either through sports affiliations or coffee clubs etc.. because their spouses have a huge network of friends and relatives that will include many single women who are in the market for a boyfriend / one-day husband.. and once you become buddies with the husband it will eventually give you access to that network of lovely women his wife knows.. either through invitations to social events they are holding.. or simply by being more direct and asking for introductions.. there's nothing that Thai women like more than match making.. because they want to see their girl friends happy and all loved-up.. but the point is that you will be farming in a much more socially up-market category.. and will reduce the risk of dating disingenuous women.. possibly saving yourself a lot of time and money in the process.. but this is where western men have got it all wrong.. in so much that it's not whether a potential Thai girlfriend is good enough for the farang.. if you are shopping in this league its all about whether the farang is good enough for them.. and I'm not talking about wealth here but in terms of character and good spirit.. because you have to get through the gatekeeper remember.. and if she gets any bad vibes then it ain't gonna happen.. no matter how big your wad might be!
Once you get a yellow book you should never need to get another residence certificate.. it's issued by the Amphur/Municipality where you live after meeting fairly stringent criteria.. and is prima-facia evidence of address.. akin to the blue book held by many citizens.. I've never been asked for a RC once when dealing with any govt agency here when I've produced my yb.. but this is not easy to get if you are on a tourist visa or are not married to a Thai!
If you want to avoid disclosing your overseas address to your bank.. or indeed other organisations you deal with in the UK.. take a look at ExpatFone which works through an app called Devyce.. for a fixed monthly fee you get a UK number with unlimited free calls and texts to UK mobiles and landline numbers (with a few exceptions).. it's app based so is effectively a VoIP service.. but the other party will never know it since it masks your location.. by giving a UK rather than overseas dial tone if somebody calls you.. and it presents your call exactly as it would if you were making the call within the UK.. so nobody gets to know where you are actually calling from.. you get free voicemail with immediate (single button) retrieval of messages.. and you can elect to port your UK mobile number over to it when you sign up.. if you want to retain your number.. and you can port it back out if you return to live in the UK one day and want to revert to a conventional network.. I've been using it for nearly a year now and it's solved all the issues of trying to maintain a UK mobile and use it overseas that plagued me.. especially as there have been reports that some UK banks are getting arsey about maintaining accounts for overseas customers.. or at least those that don't have large sums on deposit with them.. so provided you have a UK correspondence address registered with them.. such as a family members address.. then this service means they never need to know where you are actually living!
Yes that is my understanding too.. I'm simply saying it's not a fair system.. since it effectively removes the home country tax free allowance from the equation.. so you could end up paying tax on what was considered exempt income.. the only way to defeat it in the short term is to avoid bringing money into Thailand altogether.. at least until common sense prevails!
Except some countries (like the USA) tax you on worldwide income.. and it doesn't matter where that income is earned.. the reality is that income tax is not payable under any statutory law in many countries.. such as in the UK/US.. and the collection of it is actually not 'legal' but is 'accepted' nonetheless.. the answer is to abolish all forms of personal taxation on revenues and replace it with a single legislative tax on purchases.. along the lines of VAT.. which everyone has to pay since it's a point-of-sale tax collected by retailers.. so no tax returns to do and no liability to calculate in-country or cross-border.. and nobody can fudge it or avoid it and no headaches for us or the tax authorities.. simple, clean and unambiguous!