Just got back from there.
I recommend John Moore. (see my trip report Barbados 2006 for URL ) Please read the part about him having a small boat. But, he is a great guy and will take you to some good places. I dive with John on every trip there.
Do some shore diving too. As you go down the West coast highway, right across from the Prime Minister's office is Carlisle Bay. It is cordoned off so you dont get run over and there are 8 wrecks there. John will probably rent you tanks if you do a dive with him. There is a big blue pavillion, gazebo like structure easy to see from the road. There is a dive shop close to there but their compressor was broke and the guy tried to tell me to enter from his location. That would have made me have to do almost a 3/4 mile surface swim. Park at the pavillion and you are good.
The only reason I would say do a dive with High Tide is that they work with the local university on certain days and do turtle tagging. Call them and find out what days they do tagging and give it a shot.
Personally, I wouldnt dive the Stav again. It is very deep and your bottom time is like zip. I do enough deep dives here in NC that I prefer longer bottom times on vacation. I would recommend the PAMIR. It sits in 60fsw and you get a decent bottom time plus great, easy and safe swimthroughs on the ship.
Where are you staying?? My report offers a great place to stay.
Feel free to pm me with any questions you have....I have been there three times and know the island pretty well.
One thing you need to be careful about.....make sure you understand what all $$$$ quotes on anything is. Are they talking Barbados dollars...or US dollars. The exchange is normally $1 US is equal to $2 Barbados.