Yes! I knew I could count on the learned LEO luminaries to shed some light on the inner pig. :)
The author's background is interesting: Dan Vyleta
: "Born  and raised in the Ruhr Valley region of Germany to Czech expatriate parents, Vyleta attended university in the United Kingdom, getting his PhD in history from King's College at the University of Cambridge, before moving to Canada in 2007."
If German is his first language, that might explain his rather unusal (from an English perspective) use of commas. Could also explain his using an idiom such as inner pig. I've always understood the "inneren Schweinehund" (often appears in English as inner pig-dog) to be as described by veigelie in #9. Both the inner pig and der innere Schweinehund still seem, though, quite out of place in Victorian England, but I'd be happy to be proved wrong.
Fortunately, I'm not a translator. Such issues would keep me awake at night.