Assuming you're in London, England, which destinations are convenient to you may differ from what those of us in the U.S. typically think of. Where have you been diving so far, and what sort of diving do you prefer to do? How important are...
1.) Coral Reefs.
2.) Wrecks.
3.) Small, colorful tropical fish.
4.) Larger fish - decent-sized grouper, sea turtles, etc...
5.) Really big stuff - larger sharks, mantas, etc...
6.) Warm water with high viz., 'tropical aquarium' type conditions.
7.) Are you open to live-aboard diving, or mainly a land-based dive resort diver?
8.) Is it all about the diving, or does the topside scene matter?
Richard.