Line Spacing not working

[KeithEryri]

I’ve run an epub through Kepubify (on the web) and the text renders such that in my Kobo Clara BW the Line Spacing slider does nothing. So the text, while readable, isn’t that pleasurable to read.

I ran the epub through Kepubify (web version) a 2nd time making sure ‘Full Screen Reading Fixes’ was on. It then renders beautifully on my Kobo 👍🏻. Job Done, or so I thought 😮.

Editing the new epub in Sigil I changed the spelling on some words to their UK spelling, the epub reverted to fixed, uneditable Line Spacing 😐.

No amount of using Kepubify seems to fix this.

Any thoughts?

Thanks.