Unable to log in

Hi - I’m attempting to make requests but am finding that I am unable to get past the authorisation stage. The notes provided by Companies House state:

“The Companies House API takes the username as the API or stream key and ignores the password, so it can be left blank.”

As far as I can see, there is no username. There is a client id and there is a client secret. Entering the Client Id in place of “my_api_key” in the following request:

curl -XGET -u my_api_key: https://api.company-information.service.gov.uk/company/00000006

results in:

“{“error”:“Invalid Authorization”,“type”:“ch:service”}”

any assistance greatly appreciated.

kind regards,