The Case of the Undiscovered Corpse (An Alasdair and Toby and Cambridge Fellows Mystery)

Alasdair Hamilton and Toby Bowe are the darlings of post-war British cinema, playing Holmes and Watson onscreen and off. When they're called on to portray their fellow amateur detectives-Orlando Coppersmith and Jonty Stewart-not only do they find distinct challenges in depicting real people, they also become embroiled in solving a century-old murder.
How did a body lie undiscovered so long in the Stewart family vaults, who's been covering up the murder ever since and why was the victim killed in the first place?