Yeah, the Ellipse-Nelvana version completely glosses over the issue, which I thought was a little weak.
That said, I think many Tintinologists agree that the "very simple yet very complicated" non-explanation for Haddock's sudden presence (and knowledge of where Tintin was within
Wadesdah) is one of Hergé's weaker moments as well... for a very resourceful author, he seems to have dropped the ball a little in explaining this one.
Not that I can imagine a great explanation myself... the 1950 edition could have made a link between Haddock as a British naval officer (as we mostly agree he was... British, I mean) and the fact that Britain was very ubiquitous in the region at the time that version was drawn (actually up until two years prior when they pulled out of then-Palestine).
Might make for a good thread: take your shot at explaining Haddock's presence in Wadesdah