I gave my GP's surgery a call, and made an appointment with the practise nurse. We went through what examination each child should have, and when, and she then booked any due appointments.
She wrote a list in each of their red books, so I knew when I had to make appointments in the future.
You could also speak to your health visitor, I suppose, but ours was not the most charming, so I didn't bother with her.
HTH.