I’ve found cases where the previous names of companies are not included in the bulk product (Basic Company Profile Data CSV from Companies House).
Company 03587701, line from CSV file:
"COMPONENT KNOWLEDGE LIMITED","03587701","","","84 WORDSWORTH MEAD","","REDHILL","","ENGLAND","RH1 1AJ","Private Limited Company","Active","United
Kingdom","","25/06/1998","31","3","31/12/2024","31/03/2023","TOTAL EXEMPTION FULL","28/04/2017","31/03/2016","0","0","0","0","62012 - Business and domestic software development","62020 - Information
technology consultancy activities","","","0","0","http://business.data.gov.uk/id/company/03587701","","","","","","","","","","","","","","","","","","","","","14/04/2024","31/03/2023"
Previous names showing on website:
Company 02804584, line from CSV:
"JAGUAR FREIGHT SERVICES LIMITED","02804584","","","2ND FLOOR","32-33 GOSFIELD STREET, FITZROVIA","LONDON","","UNITED KINGDOM","W1W 6HL","Private Limited Company","Active","United
Kingdom","","29/03/1993","31","12","30/09/2024","31/12/2022","TOTAL EXEMPTION FULL","26/04/2017","29/03/2016","2","1","0","1","52290 - Other transportation support
activities","","","","0","0","http://business.data.gov.uk/id/company/02804584","","","","","","","","","","","","","","","","","","","","","12/04/2024","29/03/2023"
Previous names on website:
In both of these cases (and there are probably lots more), the previous name of the company is not in the bulk file. There are just empty strings for those columns in the CSV file, so the data is missing from the bulk product.