Try and get some birth dates if possible before you start looking so that you know that you have the right ancestor. The Greaves family is extremely big. Try visiting the Family Search website run by the Church Of Latter Day Saints, they have the largest online record base on Barbados ancestry. However it will only take you as far as the early 1800's if you are lucky. Anything after that will require you personally visit the Registrar's Office in Barbados and the Archives in Black Rock, St. Michael.