I took the night boat to Chumphon at 10pm and arrived at 3:30am. caught a minibus to Ranong at 5am and was at the border around 8. Stepped across via boat, stayed for fifteen minutes on the dock (i got off the boat and walked to the mainland) then we were back in Thailand around 9. Just that easy. The 'tour' officials did all the dirty work with the burmese immigration officials, so we just sat back and waited. I would have liked to have bought burma postcards, but not enough time.
I'm back safely on Ko tao and will hopefully resume diving today...