Dove 4 days in June and I couldn't recommend Big Blue Diving more! Didn't see any walesharks, unfortunately, but had some beautifully clear dives all around the island. Staff was incredibly friendly and knowledgable, particularly the German bloke, Mark, who went above and beyond the call of duty to find us interesting things to see. The diving boats were huge and provided a smooth ride, which looked far more comfortable than the skiffs other dive shops provided, and I liked how the dive groups were small and personal.
Word of advice: DO A FULL DAY DIVE! Sooooo worth the money and such an amazing way to spend the morning/afternoon.
Thanks Big Blue!