If you manage to locate the correspondence between SSS and Dom Joćo I would be grateful.
If it still exists, it would be located in the Portuguese/Brazil Archives of Dom Joćo papers. It would most likely be in French. Smith wrote and understood French, Spanish, Italian, but I am not sure about Portuguese, but, presumably, Smith would have used French in communicating with a royal.
In relation to the account of SSS and his contribution, contemporary and near contemporary accounts are always useful, but - as I’m sure you’re aware - do need to be treated with caution at times.
Treat with caution, always, of course, but it also should not be totally ignored as irrelevant. This is as close to an immediate report on a great historic event in Portugal's history that is available, yet, you a have ignored it entirely. You have lots of great references, I have ordered Interlibrary Loans for a couple, but, you did not include, or missed, one of the closest in time, published 1809.
As far as I know, Stangford's appointment as chargé d'affaires and subsequently as Envoy Extraordinary and Minister Plenipotentiary is on public record and of no need of reference.
Public record? It is simply poor historical writing to never mention the position held by a key player. Few people living today, off the top of their head, know the "public record" about who or what Strangford was or did. As a historian you can and must afford the ink to properly introduce important characters. This clearly was not done in your work, regarding Strangford.
With respect, my MA is not concerned with the activities of Sir S Smth. His appointment to command the fleet that would either escort the Portuguese court to Brazil or lay waste to Lisbon, and the Portuguese fleet, is of little consequence to the main thrust of my arguments in relation to British intervention in Portugal.
Little consequence? The complete lack of recognition of Smith's key role indicates, to any knowledgeable reader, that the events surrounding this critical and important event in Portugal's history simply has not been fully investigated by the writer or the writer is in someways biased against Royal Navy influence in the events. Which is it? Pretending to limit the scope of the work is but a poor excuse. And, as previously stated, that London sent Sir Sidney was a major statement of serious intent that would have been fully understood in the court of Lisbon.