If the British, under the command of John Whitelocke, had been able to capture Buenos Aires in July 1807 (after a much smaller British force was defeated the year before, following an initial victory in a private, unauthorized expedition), how would the British have proceeded with the River Plate region and elsewhere in southern South America?
I was thinking, until recently, that all or most of Argentina and Uruguay (as a single country) would have evolved to become like Canada or Australia in terms of being anglophone and highly developed. However, from what I understand, that is not quite realistic, given that the Buenos Aires inhabitants were much more interested in independence than in rule by either the Spanish or British Empires, and the British government was becoming more interested in economic than political influence in Latin America in general. Besides, Buenos Aires had a much larger population than Montevideo; the latter's population size was more comparable to that of Cape Town (captured by the British in 1795 and again in 1806) or that of Quebec City (captured by the British in 1759).
What I have come up with lately, therefore, are two main possibilities:
1) Buenos Aires and the rest of Argentina proper (excluding Patagonia) becomes an independent state under British suzerainty ca. 1810 (since the British are likely to have trouble dealing with Buenos Aires directly - due to insurgencies in the surrounding area, relatively big population size, not-so-strategic value, etc.), Uruguay remains a British colony (because Montevideo, its capital, is more strategic to British interests than Buenos Aires), and Patagonia evolves to be a British colony. The upshot is that Argentina is an independent country while Uruguay and Patagonia are British colonies, then dominions, and finally highly developed independent countries under the British Commonwealth.
2) Both Buenos Aires/Argentina and Uruguay become independent British client states (in the event that the British find Montevideo as well as Buenos Aires too much to deal with, owing to insurgencies around Montevideo also), and only Patagonia becomes a British colony (then dominion and finally a highly developed British Commonwealth country).
Which of these two possibilities sounds better or more realistic?