Cornell’s ‘One of Our Bastards Is Missing’ was well-received a couple of years ago, and was Hartwell/Cramered and Dozoised.
This features further adventures of his protagonist, a secret service employee of the Crown, in an alternate-ish history with the balance between warring monarchies very much a matter of concern. Cornell fleshes out the political and scientific background, with a neat take on what that falling apple might have suggested to Newtown, and has a much more far flung drama as a result.
The ability to create ‘folds’ in time and space is a more than useful plot device, akin to Dr. Who’s Tardis (Cornell is a Dr. Who novel writer) which does require a suspension of disbelief, and the evil brothers do slip into bwahahaha Let Me Explain The Plot To You mode. But I forgive them this for their multi-dimensional gravitic testicular torture.