I thought it might be useful just to have a general tried and tested thread to share our experience about things that have been useful /waste of money:
Hit
Baa baa blackout blinds - the complete darkness really seems to have helped ds sleep problems settle (more than melatonin ever did)
Miss
waterproof sheets that are just waterproof on the top- the pee just leaks down the side when ds wiggles about at night.