Lympne (pronounced as LIM) is one of those British settlements whose name is pronounced in a non-intuitive way.
Another example is Cholmondeston in Cheshire (pronounced CHUM-stan).
A prime candidate among English counties for non-intuitive pronunciations, must be Norfolk. A favourite of mine there, in this line: is
Little Hautbois, between Wroxham and Aylsham. It's pronounced "Hobbiss" or "Hobbiz". Hence the limerick -- which I've quoted a couple of times on these Forums, but never before now on "Settlement Association":
There's a robber named Robert from Hautbois,
And looting rich houses his jautbois.
Through windows he wangles
At improbable angles --
A most rubbery robber our Bautbois.