I guess if worse came to worse, all that would have to be done would be an audio capture from the VHS tape of the highest possible quality, then rip the DVD to a PC and cut out the old line and splice in the new one. If I am not mistaken, the audio on the DVD version isn't that incredibly great to begin with, so perhaps it could be done without a too bad of a drop in quality.
Though if some of the region 2 versions were in fact not tampered with, which seems likely, that would by far be the way to go.
So what we need now if for people from NTSC land (like myself) to stop replying to this thread so that someone from PAL land can speak up.