Kelt

Thanks, it helped to fix the problem. And I’ve found some other issues too on the way. Should anyone face similar problems, the steps were:

1, Reactivate podpress and re-save the episodes with the crufty enclosure. This tidied up the feed.

2, Optionally: get rid of multiple enclosures (leftover from a hosting change).

3, Re-enable PowerPress and import the episodes.

Now the feed validates.