For me it was the other way around; We had the episode "Uncle Podger Hangs a Picture" from Three Men in a Boat as a chapter in our English textbook and i remember our Teacher explicitly mentioning his middle name as "Klapka" since it was such an odd name.
If you like old genteel British Humour, you should also checkout Stephen Potter's (https://en.wikipedia.org/wiki/Stephen_Potter) series of books on Gamesmanship. Unfortunately Project Gutenberg doesn't seem to carry them and so you might have to get a hard copy. The classic movie School for Scoundrels (1960) based on these books is available on Internet Archive at https://archive.org/details/SchoolForScoundrels1959
I've known of "Three Men In A Boat" since childhood and it never occurred to me to ask what his middle name was, or that it might be this surprising.