As an update, I did another trip to Mae Sai on the 25th, as finances would not allow me to get an extension this fortnight. I had also read elsewhere on TV that they now allow 4 stamps on entry in a row, so I thought I would try. There was nobody there (farangs), and the whole process took 5 minutes from stamp out, walk to Myanmar office and pay the 500TB (no photo required to be taken) and walk back to get a new 15 day stamp at the Thai office, which will last up to the 8th of February. All the staff were very pleasant, and no-one mentioned what stamp number this was.

I will get the extension on the 31st which will take me to the end of my current stay in Thailand.

I got the 60 day extension from the lovely and efficient lady at CM Immigration, no problems.

Thanks to everyone for your suggestions and information.

Cheers,

Bill.