we're not coming from the UK as we already live in the Caribbean but we're doing a triple stay in Oct ....
Miami for a week
WDW for 11 days
Atlantis Bahamas for a week
we were supposed to go to Sandy Lane Barbados but our best friends from the UK suddenly told us they are vacationing in Atlantis so we switched to there - its very easy and convenient from the US, although IMO not "Caribbean" at all, much more US.
If you want a true Caribbean beach holiday my advice is St Lucia - wonderful island, very close to where I am, amazing beaches and resorts and not all built up and commercial like Barbados, stunning lush landscape and wonderful people. we love SLU and its an American Eagle flight from Miami through San Juan, easy. Then Virgin or BA direct flight back to the UK.
Other islands I'd recommend for "real Caribbean" - Anguilla, Marrtinique (french and a bit different), St Barts (very pricey), Antigua (lovely and laid back), Grenada (beautiful), Jamaica (FUN!!)
but St Lucia is top of the list and easy to get to from Orlando and then direct back to the UK
and if you want a nice resort .... try the Club Le Sport up at Cap Estate - we love it there.