Hi mikey_77
When you hit the submit button on a UC claim it automatically terminates all Legacy Benefits such as Housing Benefit, ESA and Income Support. You should get a 2 week HB run on. I would phone your local Council HB department to check if that happened.
UC Housing Costs are paid monthly in arrears. So the timing of the payments to the landlord will be different.
Let me know how you get on.
David
Nothing on this board constitutes legal advice - always consult a professional about specific problems