I don't even know where to begin. I made it through a chapter and a half and couldn't read any further.
Author attempted to write the vernacular of an upper class Brit, but came off sounding like an American who watched season 1 of Downton Abbey and decided to write in the vernacular of an upper class Brit.
I know a few Brits. I also watch a lot of Brit TV. Never heard anyone from the UK say they were taking their dog for a perambulation. Never heard a Brit call a napkin a serviette either.
Oh, and Americans know what Oxford is, without referring to it as, "yes, THAT Oxford."