Pleased to say incidentally that the workflow was as "fully free" as I could make it. 🙂
I was 50-50 on Feedburner, but stuck with it as you don't need to sign up to use it. Plus, you can just direct-download the ogg/mp3 files anyway.
If it progresses beyond the pilot then I may put it on YouTube. But I'm a little fearful of the comments section, tbh. 😂
My feeling is that if that does happen I'll be creating visual aids in LibreOffice Impress, then using that to export a video file.