I am trying to work out which mattress I should buy for my ds's new bed - until now he has been in an Ikea junior bed, with the corresponding mattress, which is really just a piece of foam. Does anyone know where I should start?? I am buying him a regular 3' single bed, and everyone from Mothercare to Tescos do mattresses - should he have a Mothercare-type one at his age? Also, they range from £70-odd to £hundreds!! Help appreciated!!