In these books your children will practise short a, e, i , o and u words and then long a, e, i, o and u words. I would advise you to read any tricky words for your children and then ask them to read all of the words within their ability. 
These are £7.99 for all ten story books and two workbooks. 
I have used them with my Fun Phonics pupils and I can personally recommend them. These are thin books with short, interesting stories and beautiful illustrations.