As far as I’m aware, if it’s not in the latest documentation it’s not there.
I am not aware of such a feature. Although these are now a bit old please see Companies House’ own responses about “what does search do and why?”:
https://forum.aws.chdev.org/t/officersearch-search-functionality/405/6
https://forum.aws.chdev.org/t/for-search-companies-query-what-does-it-search-and-how/1007/2