You can easily find more searching online, but to further answer your question, the trend was to move to a lesser standing in the title department. But having purely English appelations after 1917 (when Germanophobia was rampant) must have felt in some respects like a definite step up!
Duke of Teck became a Marquess (of Cambridge)
Prince Alexander of Teck became an Earl (of Athlone)
Prince Louis of Battenberg was said to have been offered a dukedom but was content to be a Marquess (of Milford Haven)
Prince Alexander of Battenberg became a Marquess (of Carisbrooke)