Jaye, do you want to order online or visit halfords? If you don't mind shopping online I would look into some "detailer" products instead of "consumer" products.
Shampoo's i like: Mothers California Gold Car Wash, Valet Pro Poseidons, Dodo Juice Born to be Mild
Clay: Mothers Claybar kit, Valet Pro Polyclay, Dodo Juice clay
Wax: Mothers FX Synwax, because it has cleaners, has a lot of fillers and protects well.
Also read the detailing guide that is a sticky here, and perhaps visit the guides on polishedbliss.co.uk