Normally, when the deadline is extended, this is correctly reported on the Companies House website. One has to apply for deadline extension before the deadline

Normally, when the deadline is extended, this is correctly reported on the Companies House website. One has to apply for deadline extension before the deadline. Between 25 March 2020 and 25 June 2020, every application that mentions COVID-19 as a reason was accepted. Additionally, all companies with accounts due date between 26 March 2020 and 29 September 2020 automatically got an extension under the Corporate Insolvency and Governance Bill. There are also all kinds of temporary changes to deadlines, the one that applies here is 1.4 from https://www.gov.uk/government/publications/the-companies-etc-filing-requirements-temporary-modifications-regulations-2020/temporary-changes-to-companies-house-filing-requirements https://www.gov.uk/government/publications/the-companies-etc... under which is exactly the 29 October 2020 listed on Companies House website.