...for an office-based editing job in a newspaper? Surely they would only be able to conduct a Basic check which would not reveal any cautions or reprimands (even cautions exempt from filtering) - right?

You're correct. As I guess you know, cautions are spent immediately so to put that in the same sentence as "unspent" shows they don't know much about the law. Cautions will only show up in a standard or enhanced check, not a basic one. If they were doing a standard or enhanced check they would ask you about ALL convictions, so this is almost certainly a basic check they are doing - the only one that this kind of job is allowed to do as it is not exempt from the ROA.

Hopefully this can be put down simply to the person in HR designing the question not knowing anything about the ROA and cautions.