Mmm... Leicester is quite a distance, probably best to spend a few days in the South west to make the travel worthwhile.
I just googled Persephone Books, it looks interesting, and how fitting that it's located behind the Jane Austen Museum!
As to swimming... I'm not sure, probably not nearby the weir as the current looks quite fast and I'd imagine they'd want to keep up appearances and not have people swimming there spoiling the view 😀