doctors notes or hospital notes? You just need to ask - there may be a form to fill in. You can either go and look at them at the surgery(gp notes) or they make copies. There is a charge for this because it tkes up time/resources
You can call the local Patient Advice and Liaison Service (PALS) for either the hospital or PCT to get more info The numbers will be on their website.
Hw old are your children? I only ask because if they are reasonably old you may not be able to look at them without their consent