Detective Sergeant William Grant is in all three of the Lost in Time 1920s London books. He is Alec Carter’s second in command. He was invalided out of Military Intelligence (“Contradiction in terms, old chap!”) after he got caught out in a gas attack in 1915. Before that he was working in the Middle East–Palestine and Egypt. He’s in his early forties by the time The Hunted and the Hind begins.
He comes from a wealthy family who were bemused by his decision to go into the police when he came out of the army, but he really didn’t feel like he wanted to do the Foreign Office thing he’d been offered. Boots on the ground and not too much responsibility seemed like a good plan for a while.
He’s always known he wasn’t attracted to women and has reached his own internal peace with that. When he meets Fenn at the beginning of Shadows on the Border, he’s a bit confused because Fenn is so androgynous and that’s not the type of chap he’s previously been attracted to.
Oh. And he’s a worker, or in his boss, Alec’s, terms a bloody magician. It runs in the family. His grandfather was apparently a skilled worker who disappeared some time in the 1860s whilst involved with the Regent’s Park group. So his father never learned all that he should have. He passed on as much as he could to Will, so Will’s not entirely ignorant, just not as well prepared as he’d have liked to be when all these peculiar things start to happen in London.
The picture I’ve included is of Cecil Beaton and Gary Cooper, some time in the 1930s. In my mind’s eye, Will is Beaton, on the left. Cooper is pretty similar to Alec, although they never flirt like these two are.