I spent 2 days trying to work out why the engine wouldn't come away from the bellhousing (my first engine removal) only to find 1 pissy bolt hidden up behind the clutch fork
I can relate to that ... until you see one taken apart (which just plops out when you get all screws out), you'd reckon it's take a fair amount of yanking just to get the two apart so even if you missed one screw & didn't know, you'd still reckon it'd be stuck and continue pulling on it like a silly monkey & wondering why it won't separate.