I noticed it's all in the letter "A". Is this normal practice for the Royal Navy? I like Audacious, not sure about Artful.
Yes, most though by no means all ship classes in the RN have a 'theme' which was often as simple as the first letter of the names, hence 'A' class (1970s Amazon class or type 21 Frigates), 'B' class (Broadsword class /type 22), 'C' class (type 22 batch 3), 'D' class (Daring class/ type 45 Destroyers), 'E' class (Echo class survey ships) and the new 'A' class (Astute class SSNs).
Previous sub classes also followed the same pattern, Swiftsure (S class) and Trafalgar (T class) SSNs as well as the SSBNs, Resolution (R) class and Vanguard (V) class. Current speculation is that the Type 26 Frigates will be 'F' class, but the RN also has a habit of going off at a tangent with class names such as 'Town' class (type 42), Tribal class (type 81), County class DLGs and the 'Duke' class (type 23). Even the Invincible class were in this pattern, as the 'I' class (Invincible, Illustrious and Indomitable, which became Ark Royal after she was laid down).