We found a lot of the stuff we were hoping to find in-store for our gluten-free guest were not to be found!
Also check-out the Sunsail provisioning website. We use this for all the heavy gear (water, rum, coconut cream etc). It's priced well (sometimes even cheaper than Riteway) and all the stuff will be on the boat when you turn up. Saves a lot of sweat and hassle!
...adding on to Bailau. You can find loads of stuff, even the non-bulky items at the cash and carry. Definitely worth starting there! You can then pay for that and leave the trolley in the doorway of the Riteway next-door and the security guard will keep an eye on it. Then do riteway...and grab a taxi to take it all back to the Sunsail base. There are some carts/trolleys around the place at the base to get it all from the cab to your yacht.
We ordered produce and eggs from Good Moon Farms, we picked what we wanted, didn't go the already prepared box route and it was AMAZING. The avocados were huge and absolutely perfect. The arugula was amazing too. We would definitely use them again. They deliver to the boat as well. We also walked over to the French store and purchased some yummy cheese, french bread and frozen croissants and frozen apple turnovers that were a huge hit!