If a renter returns an item late, you, as a lender, can charge the renter late fees. All rentals should be returned or posted back on the last day of rental to be received the next working day unless agreed otherwise.
You can decide what to charge the renter. However, the late fees should not exceed the daily rental price x daily rental fee + 25%. This means that if a rental with the daily rental price of £10 is returned 3 days late, the maximum you can charge the renter is £37.5 (10 x 3 x 1.25).
Late Fees are capped at the RRP of the item.