I originally thought chickenpox - however we don't think she has been in contact with anyone with them? There were only a few spots which never blistered and were not fluid filled!! They also were only up the back of one leg which made me think something could have got up her trouser leg whilst playing in the field at school?
They looked more like bites with a red ring around them (detail not clear in photo) and were only itchy when I looked at them otherwise she was completely oblivious to them.