Yes
nüMaps Lifetime only can be used to update the preloaded maps that came installed on your device. For example, a device preloaded with North America maps cannot be updated with nüMaps Lifetime Europe, and vice versa.
You can simply download maps you want in forum Maps section, no need to change ID, even because you should clone another UK user ID.
Cloning Nuvis,I think, is not discussed in this forum.