Please post your Anguilla experience when you get home. I am going in May and can't find any reviews. I was loking in to using Anguillian Divers because they are close to where we wil be staying in Meads By.
Anguilla is known for its old "shipwrecks." I participated in an archaeological project there in 2009 that surveyed a number of sites widely known, like the El Buen Consejo, and some only known to the locals. We dove with private parties on the project, but I recall that one of the dive shops had an exclusive license from the government to take divers to the site. If you like this kind of stuff, you should find out which one it is and just dive with them.
Words of warning, however--you won't find much "ship" at these shipwreck sites. Cannons and anchors, yes, but not an intact ship. 200-300 years of Anguilla's rough waters have taken care of all the structure.
By all means, you should try to see the El Buen Consejo anyway just to say you have been there. Picture 6 foot swells crashing into a 15 foot high razor rock wall with the wreck scattered 30 feet down at the base of the cliff. It is really exciting if you are snorkeling, less so if you have scuba tanks. It was the source of a major scandal a few years ago wherein an American who was promoting preservation of the site was found to be selling artifacts from it on Ebay. Although his actions were very hypocritical (and illegal), in answer to your question, no, he was not a member of Congress.
While you are up there, there is a Japanese fishing boat (maybe 100' long) wrecked in a cove somewhere around Scrub Island. You probably can't get to it in a large boat because of the obstructions and currents; we "found" it by accident while swimming at the base of the cliffs looking for cannons and anchors. You would probably have to swim 200 yards to go in and play on it. Lots of critters, and it still looks like a boat, since it crashed in 1979. It would be good for a snorkel trip between a deep dive off Scrub Island and a shallow dive on the Consejo.