I dived the outer Islands of the Seychelles in 2005 on Indian Ocean Explorer, IOE, it had just changed hands and we were on a repositioning voyage from Mahe to Aldabara. The diving on the outer islands is brilliant, the islands are uninhabited and so there is no fishing taking place. There is one of the few pristine reef environments in the world, evidenced by the large numbers of medium sized groupers that were just lazing about, these are the prime targeted reef fish for indigenous peoples.
Sadly the IOE was pirated by Somalis 2 year later shortly after my wife was on board on an exploratory expedition around north Madagascar. Fortunately there were no guests on board but it was over 6 months before captain and crew were released and the ship was burnt out.
Understandably there are no dive operators in the area, hopefully this may change but I'm not holding my breath