I tried Womble MPEG Video Wizard last night, thought it was worth a shot. It did reduce quality on a frame or two following the edit (up until the next I frame, basically) and for some reason decided to trim 7 frames off the end of the file (these frames only contained black anyway). But apart from that it was a quick and painless way to effect a fix for the freeze.
Just need to author with chapters, then watch the whole thing through to check for any more errors I might have missed.
Not be long, now.