I only have positive things to say about using Thai Visa Centre for my retirement visa. I had a very difficult officer at my local immigration who would stand out the front and scrutinize your application before even allowing you inside. He kept finding minor problems with my application, problems he had previously said weren't an issue. This officer is somewhat legendary for his pedantic behaviour. After having my application knocked back I turned to Thai Visa Centre who handled my visa with no issue. My passport was returned in a sealed black plastic envelope within a week or so of applying. If you want a stress free experience I have no hesitation in giving them a 5 star rating.
