If I bring proceedings in court against the mother of my nine-month old daughter, who will not let me see her, is it likely that I will have to pay child maintenance?

Yes, if child maintenance proceedings are brought against you, or you agree. By law, you are obliged to support your minor daughter, and to pay maintenance for her. If a maintenance ruling already exists, you are not entitled to take the law into your hands and cease paying child support even if your wife prevents you from seeing your daughter. Your legal proceedings for visitation rights, or breach of them, are a separate issue.