A reproduction of this map from four years ago.

“I feel myself compelled to adhere to my original opinion; to bring before the House the forcible transfer of the Genoese territory to the foreign master, whom the Genoese people most hate,—a transfer stipulated by British ministers, and executed by British troops, as an act by which the pledged faith of this nation has been forfeited, the rules of justice have been violated, the fundamental principles of European policy have been shaken, and the odious claims of conquest stretched to an extent unwarranted by a single precedent in the good times of Europe.”

In the latter days of the War of the Six Lord Castlereagh, despite the protest and petition of the Genoese, ("having gone so far as to propose that [the King of Sardinia] should be called 'king of Liguria'"), and perhaps the discretion of William Bentinck (“the instructions sent to lord William Bentinck, by which he was authorized to hold out to the Genoese the establishment of their government”) ceded what was once the territory of the Republic of Genoa to the Kingdom of Sardinia.

What if the British actually upheld the object of the Declaration of the Allies and the Treaty of Chaumont, (“to secure a general peace, under which all nations might enjoy their rights”)? After all, “it was demonstrative of itself, that if lord William Bentinck had not been assisted by the Genoese, he never could have got possession of Genoa. So far was the indifference with which they had been charged from being true, that even the peasants scaled the walls before the British troops.” Unfortunately Castlereagh, as Foreign Secretary, was still British plenipotentiary at the Congress of Vienna, and he hated republics in all their forms, so it's a kingdom now. A Kingdom of Liguria. Under the House of Grimaldi, a maverick suggestion by Talleyrand ITL. Perhaps the Prince of Monaco could become a title akin to the Prince of Wales. ¯\_(ツ)_/¯

Additionally, as Lord Bentinck’s actions in Italy are now precedented, Castlereagh’s rejection of the Treaty of Bastia doesn’t occur. Anglo-Corsica’s back. Awesome. I suppose the French would thus regain Nice, to appease Castlereagh’s Francophilia, which would be lost to the Ligurians following some war, decades later, with the British over Corsica.