Have now arrived in Chiang Mai, and have booked into a guest house. Is nice and cheap at aprox 2.50 per night for a single room with fan cooling. Air con would have been nice, but given that I am going to be going off trekking over the next few days and shall be staying in basic wooden huts I should probably get used to the warmer conditions.
I didn’t manage to get that much sleep on the train in the end as every time I got to sleep I would be woken not that much later by a noisy bit of track or the trains horn. I was slightly concerned one time when I woke up as the train had changed directions of travel whilst I was asleep.