Another book to look for is Testimony of an Irish Slave Girl by Kate McCafferty. You can get it on Amazon. it is a fictional story but with good information on life in Barbados for Irish slaves.
Also is the family name you are researching Boyle? My Barbados family is named Boyle and I have been trying to find the origins of it - both Black and White. I'd be interested to know if you are looking for this family too.