Apartment in HMO

HMO Licensing

Good afternoon

I have a Victorian property registered as a HMO but not licensed. It has four single occupancy rooms at present and the four tenants share one bathroom and one kitchen. All fire regulations are up to standard and the rooms are extremely large. I would like to convert one room into a self contained apartment with an ensuite shower room and kitchenette that would be more suitable for a couple. This room would be accessed through the main HMO entrance and be attached to the same fire system. The apartment would effectively be a stand alone area that simply uses the same access stairs. What changes with respect to the authorities would i have to make? The house would house five, but the shared facilites would only be used by three tenants.