So Satoshi was either multiple people or one clever person who was pretty switched on about OpSec.
Seriously switched on.
I could post "splendid" once in a while, but that doesn't make me based in Britain.
Yeah, all of these are indicators which over time you can collect, and build a profile of the person, and take a educated guess rather than anything concrete. So, while Franky might have been a little too quick to jump to the conclusion, those sayings are very typical of a British person, where as splendid I don't hear very often. Anyway, the indicator can also be inaccurate as it could tell us Satoshi has been infulenced by British culture, not necessarily where they were or currently based. I know Americans, and other nationalities use phrases from different countries just because they are friends or associate with international people.