>Britain's century of hegemony came afterwards
Another popular misuse of the term hegemony that's in line with the retrospective aggrandizement I mentioned earlier. It suits the monolithic power held by some ancient Greek city-states over their neighbors (whether economic, military or cultural), but not the power and influence Britain had to share with France through much of the the 19th century in the colonial world.
You can find evidence for this flawed retrospection in the modern and recurring (mis)characterizations of former British influence. For example, the alleged dominance of the British Pound among central banks (when in reality most international transactions were still settled in bullions, while half the world was effectively using the French-based LMU); its predominant role in abolishing slavery through prosecution of slave-ships (which hardly affected the US and was only accomplished with the willing participation of the French Republic); its central role in the dissemination of cultural and scientific publications (despite surveys showing that in 1870 French was by far the dominant language for global publications in agriculture, applied sciences, commerce, industry and technology). Remember that it was post-WW1 America that helped English replace French as the lingua franca, not the UK. There's a reason Disraeli was still speaking in French with Russian diplomats in 1877. That's not what a "world hegemon" does, and using such exaggerations does a serious disservice to history.