Mr. Campion's War

So this is the book I picked up a while back to read and review. I'm almost halfway done with it, but I'm not sure I'm going to make it.

The premise is great -- In 1970, a 70-year old Campion gathers his family, friends, and people who share a secret with him from 1942, when they were spies in the war. As Campion spins the tale of what happened, we will undoubtedly learn which are the good guys and which are the bad guys in the room with him in the "present."

I've never read a Campion mystery; I only know him from the Peter Davidson BBC series. I remember Campion on TV being dialog-lite, relying more on Davidson's natural charisma. Missing that in book form, we get a Campion who uses sarcastic/witty banter in every other paragraph. And it's not just him; every major character is sarcastic/witty all the time. It's tiring...