If you are looking to build on your diving experience you can start with trying any three of the Adventure Dives list (Age restrictions for Junior Open Water on some dives). 

If you choose to stop there you will be certified as an Adventure Diver. Having completed these you can add to them a Deep Dive and a Navigation Dive and you qualify as an Advanced Open Water Diver.

£165    Adventure Diver
£240    Advanced Open Water Diver ( Including 3 boat dives minimum )
All kit and manuals included.