Quarterdeck

What puzzles me with this book, as wig maker, unlike a farm hand or tanner or something, in a wig maker's workshop as the son of the owner Thomas probably had daily contact with higher up society, who he was working for. Shouldn't he have known gentleman and their language from serving his customers since being a boy? Shouldn't he have some amount of familiarity with this class and shouldn't he have acquired a little more eloquence serving them?

And, were RN lieutenants of the Napoleonic era really all talking about riding with the hounds, royal scandals, high finance and politics as the book suggests? These people have been mostly at sea since they were 12 or so. I'd imagine they haven't seen all that many "seasons" in London to rave about that topic in their wardroom.

What's really realistic with RN lieutenants of that era?

This bothered me as well, especially while attempting to decipher his thick accent. But I didn't dwell on it.

All officers enjoyed shore leave, sometimes extended, unlike the enlisted men, and were thus able to enjoy the more land-based pursuits. You will discover this when you tackle the Aubrey series.
Of course wardroom talk usually includes embellishments to bolster one's standing.