GCM-NAS can be a mixed bag. In CW, I have had absolutely heehaw, other times (edit - i should state the vast majority of trips) i have got some very tasty snacks (amuse-bouche i guess), and quite a lot of champagne in for a one hour flight! All depends on the crew (and of course the weather - tropical storm can mean no service for obvious reasons) in my experience. If i get good service great, if not, no worries, i can dig in once we are airborn again from NAS. Typically the same NAS-GCm after the long haul. PS the crews always switch at NAS - so one crew does LHR-NAS, another does NAS-GCM-NAS, yet another does NAS-LHR.

Further edit - If in Y or W, from memory and from what my parents say, service is basically on the nas-lhr leg. Meal on the way to LHR is always after NAS for obvious reasons, and that does mean eating late. My visitors always get a very large, late lunch prior to getting the flight back to london as it is near midnight before you get fed.

Sorry, yet another edit. If you do come to gcm, consider cayman airways to jamaica (or even havana) and then connect from there to the rest of the caribbean, likely also via puerto rico or st maarten. Otherwise i would recommend miami (yes miami) with AA - as you can get everywhere in the caribbean from there (often via PR and st maarten again - use a local airline once there). Although flight connection times can be rather long..... GCM has no other direct flights to anywhere else in the caribbean (airlines have promised, never happened). Those of us here usually go to mia and connect from there to get anywhere else outside of cuba or jamaica.