It all depends on which destination the aircraft is finishing in!
If the aircraft is going on to Grenada you can be sure that it will be a two class with the old cradle seat in it, if the aircraft is going to St Lucia or Tabago it will probably be the four class with first, New Club World Sleeper seat, WT +, and WT!
Im operating an ANU this week, out its the 4 class, Iv a shuttle to Grenada which is a 2 class and the rest of the trip is all 4 class!!!! So hopefully that averages out that most of the flights are 4 class out of lgw! And as the crew now what type up to a month in advance, its likely that operations know sooner!!!! But as we like to say in the airline industry..." for operational reasons" this info could change at anytime!
Hope thats of some help to you but even if its still the Cradle seat....you still get the same fab service from us cool, fun and good looking Gatwick Crew!