I am on Income Support/Income Based Job Seekers Allowance - Do I still need to make a claim for housing and council tax benefit to the Council?

The fact that you are in receipt of one of these benefits does not give an automatic entitlement to housing and council tax and a claim must always be submitted to the Council. When claiming Income Support or income based Job Seekers Allowance a housing and council tax benefit application form (called an HCTB1 form or Local Authority Input Document) is provided by the Department for Work and Pensions and should be completed and returned to them. They will pass that form to the Council but you are advised to check that the Council has received it.
Receipt of form HCTB1 or Local Authority Input Document, along with confirmation of entitlement to Income Support or income based Job Seekers Allowance, will usually, but not always, allow the Council to award housing benefit or council tax benefit without carrying out any further enquiries into your household or income. However, further information may be required (such as rent details) and you may be asked to provide this information by completing the Council's own housing and council tax benefit claim form.