I will be traveling to UVF from LHR in F with connections in MIA (23 hours/ overnight) and POS (20 hours overnight). Can I check the luggage straight through from LHR to UVF?
You will have to recover your baggage in Miami, most probably again in Piarco; you'll be glad to pick it up one last time at Hewanorra. (Brings back memories; I flew into UVF on the last AA 727 into Hewanorra.)