Yes, I believe the service is still available until the end of the working year. As I used it two months ago, I will have to go the 800K route next year :)
I am not splitting hairs, I am pointing out that the Embassy as a diplomatic mission is separate and has a separate function from the Consular affairs section which has a focus on dealing with individual persons and businesses. By all means try to get an appointment with the Ambassador to discuss your passport, see how far you get.
Then you just need to take the papers Robert mentioned to CW along with the letter from Embassy. You need the Thai form "Transfer stamp to new passport" ( I got mine from Samut Prakan immigration website). and it should be good.