Could see that one coming, Bryn, after your comments elsewhere...It's rather going to depend on the software you're using... If you have something that will open up your video's audio tracks separately, and you can then import the audio from the radio underneath and line the peaks up with those on the video before dleteing the original telecast soundtrack, you've got it made. The only problem is that the only thing I've ever assisted with in such a situation was Final Cut Pro, brilliantly effective, but costly and Mac only.... 

Bryn, I've also got both broadcasts tonight, one from FM, the other via satellite. I've not got Final Cut Pro here, but someone I occasionally consult for has. There's no harm in putting out feelers to see if I can use the rig next time I'm doing something for them...