Pitch of sound wrong on talking book

I have bought and downloaded 'Round the Horne the Complete Series One' from the iTunes Store. On playback, through the Books app on my iPhone 14 Pro Max (iOS 17.1.1), the very familiar voices are shifted up in pitch as though the recording is running too fast. This is not the case if the recording is previewed in the iTunes Store app.

This is very irritating and completely spoils the listening experience and I hesitate to download further series in case they are also wrongly pitched. Has anyone else experienced this problem and is there a known way to fix it?