Problem with 'Companies House' API

Problem with ‘Companies House’ API

GET https://api.company-information.service.gov.uk/advanced-search/companies

the company_name parameter is completely ignored in the search.

(As documented here: Companies House Public Data API: Advanced search for a company)

https://api.company-information.service.gov.uk/advanced-search/companies?start_index=1&company_name=mortgage&sic_codes=66190&incorporated_from=2022-01-01&size=200&company_status=active

brings back exactly the same list as:

https://api.company-information.service.gov.uk/advanced-search/companies?start_index=1&sic_codes=66190&incorporated_from=2022-01-01&size=200&company_status=active

This appears to be an issue with the documentation. There is an undocumented parameter “company_name_includes” which does what the “comany_name” parameter is supposed to do.