After listening to both versions, I can safely say that the "Radio Remix" is indeed the studio version, same length and everything. Maybe a better-trained ear might be able to find a difference, but to me they sound identical. So if they're both the same, the question now becomes why is it labeled a "Radio Remix"? After digging-around on the internet a bit, I found that the "Radio Remix" first appeared on the UK CD single. Usually with CD singles, the first track is the original version, followed by any edits, remixes or live versions. With this single however, the first track is the "Radio Remix", and the other two tracks are live performances of other songs. So... here are my possible explanations...
- They had a true "Radio Remix" made, but accidentally put the studio version on the disc.
- There was a miscommunication with the publisher who thought the studio version was a "Radio Remix".
- The publisher intentionally lied and labeled it as a "Radio Remix" in order to boost sales of the single.
I think the first one is the most-likely, because why would they intentionally release the studio version; which has an extended-ending, as a single meant to be played on the radio? Radio stations want their songs to be as short as possible, and will often end songs early.