My only experience of this was with my 2 year old Seat Altea XL, used as a taxi. 135k miles on it with full Seat service history. When I threw it back I did the following to it...
1. Replaced drivers seat base foam. It had collapsed.
2. Removed and washed the rear seat covers. The interior was a medium grey which waterstained badly.
3. Replaced the undertrays. Fully loaded it used to catch the back end of them on speed humps.
4. Gave it a thorough wash and polish.
5. Replaced the binnacle cover. Had a notch cut into it for taxi wiring.
All the above cost about £120 and time.
The bloke who inspected it simply looked around it taking notes and took a few general pictures of the car. His only immediate concern was that the car was driving, taxed, MoT'd where applicable and that the tyres were legal.
Stone chips and the like are acceptable if comesurate with mileage. Any obvious damage or signs of neglect will cost you dearly and with a PCP, any excess mileage charges will see your bank balance battered.
If I may be so bold, look at the numbers for HP over a 4/5 years and hand it back at the halfway point. Check the small print and ask the question directly. But you should save most of the deposit/better interest/no mileage limitations...
HTH