Apologies but the documentation is currently incorrect, and why its not working, including the “explore this API” functionality.
The sequence should be :
- Call filing history (as above)
- Call document api for transaction you are interested in.
https://document-api.companieshouse.gov.uk/document/{doc-id}/content
2.1 The document API returns a 302 Moved response with a Location: header pointing at the document
3. Get document by following the Location: URL. This can only be done once, without repeating 2, and must be done within a short time window, before it expires.
The following forum post provides further information which maybe of assistance.