Adding a disclaimer document to envelopes

I work at a law firm in the UK. We send out deeds that also need to be signed by a witness. When we do this we want to be able to send alongside the deed an information sheet about what is involved as signing as a witness (their responsibilities, the process they need to follow to make it legally binding etc).  Our account manager suggested adding an Electronic Record and Signature Disclosure (ERSD).  However I have looked into this and it seems this gets added as standard to all envelopes sent from our account (not all documents that we send are deeds) and the ERSD as I understand it, is also required it to be signed.  The document we want to add is just for information.  Does anyone have any suggestions on how we can create the option of adding this document to some of our envelopes?

We also use another esigning provider which unfortunately doesn’t allow you to sign as a witness (hence why we use DocuSign) and this has the option to customise the email sent with the link to sign the document so we can add our own wording and links to disclaimers but I don’t believe DocuSign has that functionality.