I must say I fell in love with Singita! It's really a must. I've heard many positive things about North Island as well. But if I were you, I'd stay in South Africa when going on Safari there. I love Cape Town, though it's not really on the beach and it's not very idyllic. For the best beaches you should head to th Seychelles indeed. Don't go to Mauritius, it's overdeveloped and the beaches are not as nice as on the Seychelles. Other great Seychelles properties are the Banyan Tree, Fregate Island and Lemuria.