So the short answer is no, we can't, but i'll expand with a few things to explain why:
So by utilising the met police for the whole map, it allows us to save a large amount of server storage space on vehicles and uniforms. These savings apply less load to the server, especially during peak times, allowing for smoother gameplay.
Implementing kent police (which would require new EUP and Vehicles at least) would require adding new uniforms for every division, new vehicles for every division, and this would significantly ramp up the file size of the server, and would as a result substantially impede server performance.
With that in mind, i'll be moving this to declined