Hound Ltd commenced trading on 1 June 2024 and prepared its first set of financial accounts for a 15-month long period ending on 31 August 2025. What is the statutory filing deadline for submitting its corporation tax returns for this period of account?

Giant Ltd is classified as a large company and is required to pay its corporation tax liabilities by quarterly installments. For a short eight-month accounting period ended 31 August 2024, the company estimated its total corporation tax liability to be £400,000. What would be the amount and due date of Giant Ltd's first installment?