Finished last night.
To the resident Christie (and Miss Marple) fans: Do you recall Christie saying anywhere that Colonel Melchett is a Scot? Because that's the accent that Richard E. Grant gives him. I totally wouldn't rule out that he's got a point -- he picked up on Christie's characterization of Lawrence Redding as Irish, too, and that's easy enough to miss as it is -- but if he's right about Melchett, then boy do I have to reread all of the Miss Marple mysteries that are actually set in St. Mary Mead to see what I've been missing about Melchett.