OP. I'd recommend a second opinion too, and bringing your question to this forum is a good idea too.
Not to hijack the topic, but.... I just had a video colonoscopy, general anesthesia, done 4 months ago at San Paulo Hospital, Hua Hin. $600 USD.
Very professional staff and equipment. I'm 74 and they found no polyps. I ask for and readily received full review documents and color pictures they took. I am very impressed with their work.