Fifth Temeraire book.
Invasion of England by Napoleon brings Laurence temporarily away from the gallows, his sentence for treason stayed for the moment, and Temeraire from the breeding grounds to stave off the French no-goodniks. Temeraire begins to introduce his radical dragon-ist ideas, so after the victory over Napoleon, he and Laurence are transported to Australia. Presumably book six will be a down under book, at least to start with. Although from there, it might not be a surprise to see a return visit to China.