When I go to that URL on a stock, direct FF install, I still see that notice.

My Hero isn’t actually Irish, but it does star Ardal O’Hanlon (Father Dougal) for almost its entire run, so it may scratch the itch.

Yep, it’s probably easier to get an Android device and install readers on it than to try for a prepackaged FOSS reader.

I use several apps on my Android phone, but mostly Kindle (for Kindle, duh), PDF Reader (for PDFs, duh again), and Lithium (mostly for EPUB but pretty much everything else, too). I get most of my e-books as DRM-free EPUBs and PDFs.