Why Russian battleship purchases might never reach Russia

How would Germany respond if Russia bought Revenge- and Conte di Cavour-derived battleships from Britain and Italy?

Probably with little change to its existing program; war and revolution are more likely to keep the ships in British and Italian service than deliver them to Russia.

Germany is already building its own capital ships, so the Russian order does not create an obvious new German response. The more immediate problem is delivery: once war begins, the British-built ship is likely to serve with the Grand Fleet and the Italian-built ship with the Regia Marina. Revolution then makes transfer to the new Soviet state politically uncertain. Britain might impound its hull permanently, leaving the proposed Russian fleet expansion as additional Allied wartime capacity instead.