It's just a word she's heard goes with rent.What's she on about with peppercorn rent?! I pay peppercorn rent or ground rent as a leaseholder. Is she getting confused with Ye Olden Days and Surfs and Land Squires?
My new build office pays a few quid a month peppercorn rent to the developer for Reasons. And it's literally a very few quid.
I sincerely doubt there is anything peppercorn about the rent incomes Jack's rellies get (or got).