As a Brit, I've been to Cuba as have many European & Canadian flyfishers. It's great.
The fishery you refer to is probably the Jardinas de la Reina, a chain of coral cays some 40 miles off the central south coast of Cuba. This chain is practically as big as the Florida Keys. An Italian co has the sole franchise, & indeed apart from some local lobster fishers are the only inhabitants. Outfitters Roxtons of the UK act as marketing agents. Their merger with Frontiers earlier in the year was called off becos of Sept 11.
Accommodation is on a houseboat & is probably only of a standard that would keep 30% of wives happy! The fishing is great. Lots of bones including big ones. Many but small tarpon, with a few to 50 lbs. A good place for grand slams with 1-2 permit caught most weeks. Yours truly had a 3 lb bone, 50 lb tarpon & the fly in the mouth of a permit one March day 4 yrs ago. Woe!
Access is a drawback. About a 7 hour bus ride from Havana to Jucaro & then 4 hours by boat. As I understand it, several Americans go via e.g. Nassau & ask for their passports not to be stamped on entry.
Other good Cuban fishing is in the Bay of Pigs (!), but this is unlikely to be developed as reportedly Castro has a villa there, & the thought of lots of Americans there does not appeal to him!
Also try Cayo Largo, an island off the south coast with an air connection to Havana. Here, as I understand it, you can be guided, fish DIY, or arrange to be dropped on out islands & picked up later. Would be good value. Accommodation & food in Cuba is of a uniformly medium low standard.
I have heard it said that the islands off the north coast are fished out commercially.