Pronounced "Fungy" with a hard 'g' if Wodehouse is to be believed.
I live in Somerset, which for some reason has a reputation for some weird place names. It does too but no worse than the rest of the country.
Hatch Beauchamp (Hatch Beech'um), Ryme Intrinseca (whatevs), Tintinhull (Tint'nll), Crewkerne (Crook'un). Oh and there's a bloody great chalk outline of a bloke with a massive club at Cerne Abbas.
You may have heard of Glastonbury. That is pronounced in these parts something like: Glasstunbree (run all the syllables together, shorten all the sounds except the mildly sibilant ss and trailing ee). The music festival is actually held near Pilton but Glasto sounds much cooler.
Others I've come across over the years, some in Wodehouse, some not:
Featherstonehaugh --> Fanshawe
Cholmondeley --> Chumley
Mainwaring --> Mannering
Wickhammersley --> Wickumsly
Menzies --> Mingis
The last immortalized in the limerick:
A lively young damsel named Menzies
Inquired "Do you know what this thenzies?"
Her aunt with a gasp
Replied "It's a wasp!"
"And you're holding the end where the stenzies"
Featherstonehaugh -> Festonay (I made mine up - do you have a citation ... to be honest, "fanshaw" sounds right)
Loughborough -> Luffbru
Your others, I agree with. eg (Mr) Mainwaring - Dad's Army.
https://en.wikipedia.org/wiki/Stanley_Featherstonehaugh_Ukri...
There's also https://www.cntraveler.com/story/youre-probably-pronouncing-...
"...You could try hundreds of pronunciations of "Cholmondeley" (in Cheshire) before hitting on "chumley," and the sixteen-letter "Featherstonhaugh" (in Northumberland) drops more than half its weight to become "fanshaw."..."
etc.
That would of course be the faithful sidekick of Tennessee Tuxedo, who is the Linux mascot in an alternate universe.
https://en.wikipedia.org/wiki/The_Man_Who_Could_Work_Miracle...