Thank you all so very much. I will try the Audio recompress later.
However, I noted that 100.1 percent speed adjustment wouldn’t have accounted for my 5 frames fast every 20 seconds (sorry, I keep saying that and it is more simple to say 1 frame every 4 seconds). So I decided to just drag the MiniDV footage onto my timeline to see where it was going off. Turns out, Final Cut does a rudimentary reverse telecine process on 29.97 footage when you dump it onto a 23.98 timeline. So I am now able to match precisely the cuts from the original edit. Turns out I had quite a high error rate when I did it by calculating the timecode equivalents between 29.97 and 23.98 (only ever attempt this method of matchback for a World Record in stupidity). So I should be alright now.
Just out of interest. If I get the cuts to match will I still need to compress the audio to 47~~~ Hz? Now that I know which format I want to work on (23.98) thanks to your kind suggestions, I think I will be able to do some more searches for answers already posted here.
Thanks again.
An invaluable resource for getting out of problem solving thought loops.