I was always under the impression that on a “normal" 4 exit roundabout (i.e. two roads crossing), you would indicate left if going left, right if going right, and no indication if going straight on. Then whichever way you're going you indicate left when passing the exit before. However, a number of drivers indicate right when going straight on, which means I stop expecting them to continue around but could've entered the roundabout. Am I incorrect here? Was there a time when something different was taught?
Yeah, exactly, we never indicate left (your right).
I mean, I don't particularly love our system, especially when turning into a roundabout and there's a car coming up to the exit that you want to enter from, then there's no way to tell, whether they'll take that exit or not, until quite late, because their indicator light is facing away from you.
But yeah, it feels like the system you described would fall apart rather quickly, too, with multi-lane roundabouts or just oddly shaped roundabouts where, for example, you could interpret them as a T-junction or not.