GeoffR, first of all the "Refresh pages every" menu in the Reading settings looks like the photo you have posted (in the Kobo Aura One).
Talking about the line spacing patch, i'll try to explain but i am afraid that my English is poor. However, the Kobo Aura One has
15 line spacing values by default; I activated the 10 line spacing values patch, and only a few values worked, while other values were the same before the patch.
I hope i was clear; however i think that the only way to have this patch is to create it for 15 line spacing values
