Ballywatticock is a contender. Shitterton is funny because it literally means what you think it means as it was next to an open sewer. When I was younger I thought Ballybogey was hilarious.

Technically you could count "Derry/Londonderry" as a de facto placename as a whole by how it's used, even though it is technically two names of the same place side by side. But I realised how bizarre it is for people who don't know about the history of it, and come into a bus or a train station and hear an announcement for "Derry-London-Derry" or see "Londonderry Derry" on Google Maps.

Another one I like is Torpenhow Hill. Basically Tor means hill. Then someone invaded and the name changed, saw a hill at Tor and called it Tor Pen, which also means hill. Then another group comes along and adds their word for Hill as "How", and then finally we see the hill and add the word "Hill"

Lisburn is another contender. While most places with "burn" in the name refers to a river, Lisburn is named that way because it's the rebuilt part of Lisnagarvey that burned down. There's even a phoenix in the armorial achievement.