We found a great place last year, MayaBreeze Inn. It's on the Placencia peninsula. They can arrange any and all tours and diving. Look them over. They are North of Roberts Grove.
They have cabins on the beach, good sized and priced as well, nicely decorated and very, very clean. Buddy and Tressa are great hosts.
I just talked with Tressa the other night. We're going back there again this next trip.
For some reason their email isn't working on the website, call the 800 number
( email may be working by now )
Ask all the questions you want, they will honestly answer them