John Royston Lewis (1933- ) published some 70 volumes of crime fiction (https://www.bookseriesinorder.com/roy-lewis/) under the name Roy Lewis, including 22 stand-alone novels and three series. (Stop, You’re Killing Me!, http://www.stopyourekillingme.com, lists about 55. It’s possible this Roy Lewis has been confused with Roy H. Lewis, another mystery writer.) John Crow, his first protagonist, is a police inspector; the second is Eric Ward, a former policeman who became a solicitor. Arnold Landon, a city planner and a medieval historian, especially knowledgeable of old buildings, features in his longest running series.  

Most Cunning Workmen (William Collins Sons, 1984) is the second book about Arnold Landon. His manager is still fulminating over the publicity that Landon’s first case generated but can’t stop him from spending his vacation time cataloging the records and personal papers in Oakham Manor at the request of the local heritage society. Oakham Manor dates back several centuries, beautifully situated in Northumberland. Unfortunately the building’s future is in question, as its ownership is being challenged by a cousin to the current owner Tina Vallance who is in no financial position to buy the cousin out. In addition, her father, who died a few months previously, accepted an option from an American computer company to buy the mansion. The owner of the company and his staff are on site, deciding how to use the building and meeting potential European partners in an expansion of the business.

While the atmosphere is uncomfortable, and Landon feels deeply sorry for Tina, there’s not much he can do but complete his assigned work as quickly as possible. The discovery of a body brings the local police around. The homicide victim is a stranger to the area residents and everyone assumes he was connected to the Americans staying at Oakham Manor. The Americans deny knowledge of him or his reason for being in the vicinity but the inspector does not believe them. Then the owner of the computer company discovers unusual sales of the company’s shares and accuses his staff of insider trading, creating even more tension. Matters culminate in a meeting of the prospective European partners and the computer firm representatives, which Landon attends on a fairly thin pretext.

The mystery and the characters, while credible and competently executed, are overshadowed by the lyrical descriptions of the manor and its surroundings. The author knew his ancient structures and it shows. Fans of medieval English history should especially enjoy the bits of 1600s text quoted from old legal documents.