If you want another probable dead end I did find a Bank of England will for George Brown, gentleman, of Bonavista Island. This is not the same George as the son of William as this George died in 1819 or 1820 and was married to Elizabeth. Interestingly his will states that Elizabeth (I think) was from Poole, Dorset and his main beneficiaries are James and John Bristowe - a surname which crops up with the other George Brown.
The image is moderately legible but behind a paywall. If you send me a private message with your email I can send you a copy.
First name(s) George
Last name Brown
Date 1820
Entry year 1820
Place Bonavista Island of Newfoundland
County Overseas
Description BROWN George. Gent of Bonavista Island of Newfoundland
Reg 2881
Record set Bank Of England Wills Extracts 1717-1845
Category Birth, Marriage, Death & Parish Records
Subcategory Wills & Probate
Collections from Great Britain, UK None