Annual Accounts needs to be filed at once in a year period. It is an annual filing obligation with Companies House.
You can check your due date in the Company Details section from your MadeSimple account; just click on My Companies (login required), and then click on your company name. It will be listed next to: "Next Accounts Due:"
Alterntively you will be able to find the filing date directly from your dedicated listing on Companies House's public register by searching for your company:
Companies House normally gives you 8 months from the ARD to get the accounts filed to allow plenty of time to gather all necessary information.