Bonnies arch is very well situated and you have your own good shore dive site right there! There is a Foster's Food Fair in West Bay to provide your grocery needs. Good dining nearby at Alfresco and Cracked Conch Macabuca.
You are close to the shore diving at Lighthouse, Cobalt Coast and Turtle Reef as well and away from the hustle and bustle of Georgetown and the bottom half of Seven Mile Beach.
We use Andy's Car Rental as it seems to be a bit less expensive than the others.
There are many good dive ops on the west side of the island that dive north as well when weather permits. We like DNS and Wall to Wall but you will find that most of the other operators have loyal followers as well. All good as long as they also provide big boat, small group service.
Dive Tech is the operator for lighthouse and Cobalt Coast, maybe they can provide you with a boat, shore, tank package that meets your needs. They can also do a refresher for you if you need it. Do not have any personal experience with their rental gear.