The Curse of Braeburn Castle by Karen Baugh Menuhin
Heathcliff Lennox (please call him Lennox) was in WW 1 and his butler Greggs, with whom he has an entertaining and humorous relationship, was his batman. Now back home, Lennox is having a bit of an adjustment to civilian life. He prefers solitary activities like fishing or walking his dog, Mr. Fogg, in the countryside around his slowly declining estate. However, he has friends and family that can bring him out into the world beyond his gates. Lennox is likable and intelligent, tongue-tied around women, but loyal and honest. The Curse of Braeburn Castle is the third mystery I've read featuring him and may be the best so far.
This third one begins when Lennox's newly-married friend, former detective Swift, asks him to come to Braeburn Castle to help with the discovery of a centuries-old skeleton. The discovery of the skeletons has brought a team of archaeologists to the castle, a group Swift doesn't trust, and now the skull and it's...