I have done my non o in the UK and they have asked for insurance too, I thought it was just non OA, but Thai embassy in London asked me to provide health insurance, as it was I have taken it out to start on our arrival date, but they definitely are asking for it, my application has anyway.
what do you put in the Thai national id number? It has a red astrix so you have to fill it in, I'm guessing westerners living there don't get a Thai id number.