not sure Neil. I would be inclined to not risk it with children. Its probably better to book in advance. As long as you don't have to pay in advance you can then book out after a few days- just check the T&Cs before going ahead with the booking just incase. Have you been to Thailand before?

I've seen plenty of people from Europe staying in the hotels in Thailand with kids including some of the cheaper end accomodation...its only us Brits who seem a little reluctant to do it.

You could book in a plusher hotel in Ao Nang for a few days and do a little research when you get there. We go in mid-March and theres usually accomodation available...not sure about the Easter period though. I've seen perfectly nice hotels going for £12 - £15 a night so it does not have to be as simple as a beach hut.