I am currently in Thailand on an O-A visa. I am aware that I will require health insurance when I apply for an extension. I want to synchronise the dates of the health policy with the visa extension so that I have the required full-year cover at the time of extension application so I was planning to get health cover at the time of the first extension application. However, I also want to leave Thailand to travel a few times before then. Will I have problems getting back into Thailand on the existing O-A without health insurance?