I could try that, but I don't want any tags to be altered by MB because of the editing issue with APE vs ID3.
What's odd with the 'duplicate tags' issue is that it is just the tags I have 'customised' that repeat in the MB display. Album, title, year, etc, never get duplicated (and they also exist twice - in both APE and ID3), only Intro, Geographical.
Maybe I have messed up the 'Custom Tags' settings, which seem very complicated to me!