Sources for British Guiana research are rather hard to come by. I’ve just (re)discovered the London Gazette archives. The London, Edinburgh, and Belfast Gazettes are the official newspapers of record in the United Kingdom and include notices relating to State, Parliament, Planning, Transport, Public Finance.
A large proportion of notices published in the London, Edinburgh and Belfast Gazettes are mandatory, including Insolvency and Bankruptcy notices. Clicking on Archive>Full Search allows search of archives that cover most of the nineteenth and twentieth centuries and seem to go back as far as back as 1752.
Searching for British Guiana as of 24-July-2007 brings up 2264 entries, the oldest being from 18-February-1831:
The King has been pleased to appoint Major-General Sir Benjamin D’Urban, K. C. B. to be Governor and Commander in Chief of British Guiana, comprehending the Colonies of Demerary, Essequibo, and Berbice.
Searching for “Van Cooten” and variations brings up 20 entries, many from the Demerara colony in the 1820’s. Searching for “Demerary” results in 1002 gazettes dating back to 27-November-1784.
NOTICE is hereby given to tbe Officers and Seamen who were actually on Board His Majesty’s Sloop Fly, Milham Ponsonby, Esq; Commander, at the Capture of the Cargo of the Brigantine Hope, Hans Pieter Fynboe, Master, from Demerary to Amsterdam, condemned in the Court of Vice Admiralty of Tobago, and sold there, that the Shares of Prize Money due to the said Officers and Seamen shall be paid unto them on Monday the 6th Day of December next, at the French Horn, in Crutched-fryars; and the Shares remaining undemanded will be recalled the First Monday in every Month for Three Years to come.
More research in this resource is needed.