When you print a receipt from Patrons -> Account, the slip is generated from a template, printfeercpt.tt. This should be something which can be configured in Notices & Slips.
*** This bug has been marked as a duplicate of bug 22761 ***
I'm pretty sure that bug 22761 and bug 22809 cover this.. I just somehow completely missed the slips when looking yesterday.
Do these cover all your use cases Owen?