I am a qualified diver (Advanced SSI) and dived all over the world, but not for a while. Olymian Divers is easily the most professional outfit I've used in 11 years. They're friendly and understanding and I was most impressed that the cost was the cost. No extras for transport, etc. Their beach office was clean and tidy and also reflective of their equipment. Either it's new or it's bloody well looked after!
No hesitation in recommending.
PS Zenobia is a fantastic dive.