Assuming you're right, that's a shame, as the producers of FW are usually pretty accurate with this stuff. I do remember, however, when we took our school group on a mock WW2 evacuation, we hired a 1940s Routemaster of a type that was still in public service in the 1970s and was still being used regularly by the hire company for school runs in the 1980s. Could it be you remember it from the '60s (as I do), or are you one of those walking bus encyclopedia people like the ones at our local transport museum (in which case, that's disappointing on the producers' part)?
The Finnish state flag is a variant of the national flag and has a red-coloured coat of arms in its centre. Assuming the contestants weren't being specifically asked for a national flag then the answer would be correct.