The choice of topics, really. This was for (I think) an entrance exam, and so the only topic I think even vaguely suitable to write about without forewarning is "English country life in the 18th century." The Battle of Blenheim and the character of Rachel Lady Castlewood can only be attempted if you already know about those (very specific) things, and duelling is broad, and odd.
I guess it's loosely equivalent to an essay topic today on:
1. English city life in the 19th century.
2. The Battle of the Somme
3. The character of Lady Chatterley
4. Apartheid
I'd expect that whilst they might seem absurdly dated 100 years from now many contemporary British Cambridge applicants today could confidently write essays on (2), a fair few on (3). I'd be really happy if (4) seemed like an odd subject in 100 years' time.
I don't know whether this is an entrance exam and that would definitely change things.
But either way, according to Wikipedia, dueling was a part of British culture though the early 1800s, the last fatal duel was in 1856. Meaning a typical candidate from an elite family in 1899 will have a living relative who has probably at least read public discourse about dueling, and there's a good chance the subject has come up at least once during primary education.
Scotland's last-ever duel with swords was fought in the same year: 1899.
"Swords were drawn and blood was spilled over the election battle of the University Rector."
It was in a semi-public place (the Glasgow University Union building) and may have been reported at the time. Thus, duelling may have been in the news at the time.
In a bold attempt to prove myself wrong I offer this other link that suggests that the story (well-known to alumni of Glasgow University, such as myself) may have been a fictional, satirical sketch written for the student magazine.
"It found no other mention of the event in contemporary university records, newspapers or court summaries."
