EUSS Family Permit to Pre-Settles Status (Lounes)

Hoping someone can answer my question:

Partner just arrived in UK on EUSS Family Permit and is now applying for pre-settled status by post (I am both EU and naturalised UK citizen so this is a Lounes case). I was surprised to see nothing on the application form relating to applicant-sponsor relationship, i.e. when we'd met, how long we've been cohabiting etc etc unlike when we'd applied for partner's EUSS Family Permit and, the form's not asking to submit proof of relationship docs (which we obviously submitted for the Family Permit application). Having read EUSS caseworker guidelelines my impression is partner's Family Permit is sufficient to prove relationship for pre-settled status or am I wrong? Just wondering if we need to submit all the docs proving relationship that we submitted for partner's Family Permit as I am going to need quite a bit of ink and paper for this!

Thanks