Client has private tenancy since Aug 2008. Rent is £85.00. His H.B is £55.00.

This is the Local Housing Allowance for shared accommodation?

All utilities are included in the rent figure. (he has own room, en-suite bathroom and a shared kitchen). CAB have been helping to claim a DHP.

Customer says Council tax included in the rent too. Doesn't seem to state this on the tenancy.

See page 38 of Disability rights handbook. Is there a chance of getting more H.B? Why should he contribute towards Council Tax?

CTB can only be paid where the clmt (or partner) is directly liable. If there is no (direct) liability, there is no entitlement to CTB.