Thanks for the pointer to that thread... my search for "stroller" didn't turn it up.

As you say, though, it's hard to discern a clear answer from the replies there; one refers to the free checking of car-seats; most relate to whether it's worth bringing a car seat from Germany to the UK. With a much narrower range of options here in Brazil, and a much larger cost differential for anything decent, the calculus is a bit different in my case - but the point would be moot if checking the items isn't permitted without the infant in tow.