Originally Posted by kiwidude
@davidfor - I'm afraid that functionality is just way too niche to consider for this plugin. There is such a small range of use cases where it would work. I would suggest the majority of users get their ebooks from a wide range of sources/publishers, which makes it impossible to do such a substitution without doing irreperable harm to the ebook.
I think you would be better off having a bespoke plugin that does specifically just this function. Or possibly even having it as a Sigil plugin (though this is not possible yet, but might be one day if it ever gets a plugin API).
I'll have to accept that. I though there would be more interest, but there obviously isn't.
As to a plugin or something to do this, maybe in the future. At the moment, I'll stick with my hacked version of Modify ePub