1 house - 2 tenancy's - council tax

I have a 2 bed house with 2 people both on LHA with a tenancy each, the council have assessed the payments and awarded the LHA but they now want to put the house down as a HMO and charge me the landlord full council tax.

Is this correct, can the council list this as a HMO and do I need to pay the council tax?

Any advice is duly welcome.

Andy