Slave & Slave owner records:

All Former British Colonial Dependencies, Slave Registers, 1813-1834

Ancestry offers access for free (you may have to register):

A search for 'Douglas' slaves & slave owners gives over 900 records

https://www.ancestry.co.uk/search/collections/1129/?name=_douglas&a......

https://douglashistory.ning.com/profiles/blog/show?id=3482022%3ABlo...

Slaves, Slave owners and other records in Jamaica

Held on the familysearch website (register for free):

Jamaica, Church of England Parish Register Transcripts, 1664-1880
Jamaica Births and Baptisms, 1752-1920

A search on the name 'Douglas' reveals over 7000 individual records in Jamaica.

https://www.familysearch.org/en/search/record/results?count=20&...

https://douglashistory.ning.com/profiles/blog/show?id=3482022%3ABlo...

Certificates of freedom of emancipated peoples on Jamaica.

Manumission - Manumission is the act of freeing slaves by their owners, also known as enfranchisement or emancipation.

- Manumission records held in the British Library database, access for free

https://eap.bl.uk/collection/EAP148-3-1/search

Best regards