CPT Keene doesn't wear a kilt in the final scene like his army; he's at a dinner party so he's wearing tartan trousers instead. It's significant during the Khalabar invasion, why? Because CPT Keene "wears the trousers" in his army's relationship.
Also, earlier in the film, he claims that underwear is only to be worn when ladies are present and is also shamed when Sir Sidney asks him to show that he's not wearing underwear under his kilt when he clearly is. He's probably wearing trousers because he could either secretly wear underwear (or not) and because he's dining with Princess Jelhi and Lady Joan.
The Khasi calls his daughter the "Light Of My Darkness", which is significant when she does a Heel–Face Turn and helps the British Army (the heroes of the movie) when her father plans an invasion. Hence the trope Light Is Good.
Sid and Joan's surname is Ruff-Diamond, probably a play-on word for "diamond in the rough", which means when a good quality of a person or object is hidden underneath a pile of bad qualities. Could this be why they're never acting like a sir and his lady because the good qualities they have (for example, conquering most of the The British Empire and loved by all) are hidden beneath their bad qualities (willingly cheating on each other, lazing around and having sex all the time instead of keeping the Empire in check)?
A bit of Fridge Logic here, too: The Khasi having numbered wives is constantly referenced throughout the movie. The Khasi points out that his daughter's mother is marked #32 and MAJ Shorthouse makes a mental note of the numbers on the wives that show up to the mansion. Do all the Khasi's women have numbers on their bodies? Could Princess Jelhi also be numbered? That would explain why Sid points out that #5 hasn't shown up, implying that the wives are visiting in rank order.
Is it me, or is the Khasi just a pimp with a lot of prostitutes?
Sidney is found out by Joan that he's been seeing women while she was gone and throws vases at his head. When he and his secretary Shorthouse are reliving the events, Shorthouse says, "Lady Joan's aim's sure improved this time." Has Sid cheated on her before?
Maybe not. It could be referring to how he's messed up loads of times in the past and she's thrown stuff at him in fury.
