Immigrationboards.com

I am EU national who have received the Document Certifying Permanent Residence. The Home Office clearly states under:https://www.gov.uk/eea-registration-cer ... -residence

Using your document to apply for citizenship
You can only use your permanent residence document to apply for British citizenship after you’ve lived in the UK for 6 years.
That means you must wait another 12 months if you’ve only lived in the UK for 5 years when you get your document.

BUT

The application form (Feb 2017) states nothing about Permanent Residence Document and on its page number 12 and requests for EEA nationals Permanent Residence Card instead:

EEA and Swiss nationals exercising free movement rights:
Please state the number of your Permanent Residence Card and the date of issue.

Just for record: The Permanent Residence Document has no number (it has only "Case ID").

Do I need now after obtaining this Permanent Residence Document still apply for this Permanent Residence Card? If not what should I write on the form in this section?

Is there any official guidance online? Have not found anything in the AN-Booklet or AN-Guidance

Thank you for any advice!

If you have a document stating you have permanent residency, with date from, or document stating you have indefinite leave to remain that is sufficient. I had a residence card and letter from the mid-80s stating this and it was accepted. There is no need to apply for the PR card, it is just confirmation that you have PR. Clearly you don't have a card so can't fill in those fields.
Unless I have missed something