Hello @admarshall2002 Can you check that the API Key you are using is for the ‘Live’ service and that it is currently active. There is a Test service we have at Companies House which is a sandboxed account and has a slightly different Url.
Live Endpoint:
https://api.company-information.service.gov.uk
Test Endpoint:
https://api-sandbox.company-information.service.gov.uk
Below is a code snippet that I used to get a JSON object back.
import requests
company_number = 'XXXXXXXX'
api_key = 'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx:'
url = 'https://api.company-information.service.gov.uk/company/{company_number}'.format(company_number=company_number)
profile = requests.get(url, auth=(api_key,''))
data = profile.json()
print data