I would go to immigration 2 weeks before expiry and apply for 2nd STV extension. STV ends Sep at this stage so hopefully as long as you apply before end of Sep you will be ok.
I'm also on STV and this is my understanding.
Can not change STV to any other visa in Thailand you must leave.
Hi, can I ask what insurance company you used? I'm currently in Thailand on a STV and looking to come back to Aus to apply for OA after my 9 months on STV
Im on STV too...I would just request extension before Sep. My last extension I did 2 and a bit weeks before expiry and was still stamped 90 days from original expiry. I'm in Phuket