The cooling off period is mandatory if you would like to extend your visa with the same sponsor. But in case, if you find a different sponsor, There is no cooling off period required for you to apply a new work visa.

The query which I wanted to clarify is, My current employer/visa sponsor says that because I am deputed in the UK on a GBM visa with a "sub route category "called "Bespoke Model visa" tailored for some employee tax benefits . With this type of visa, my employer is saying they can't apply for a new ...