Had a couple with the Oak interior and it wasn't bad at all, but does show wear quicker than black - I think you can get leather dye if that's what you want to do. or there are various leather feed treatments around.
the satnav is OK, but lacks postcode input which is a pain. Last available discs are 2015 - check it works as the laser gets weak and can fail as they get older. If buying new discs, get used ones off ebay as volvo still charge around £200 as far as I know. The screen was also used as a TV and the car may have a tuner built in, if so this will be analogue so is as much use as a chocolate fireguard these days.
This age of car can suffer a failing dashboard cluster (volvo speak is DIM), its around a £100 repair - if anything on the dash is suspect, factor this in. May be as little as the highbeam warning light not working. Also check the little screen at the bottom left is working, will say door open etc at the appropriate times. It's also used to advise if there are any faults on the car (but not what the fault is) some unscrupulous sellers have been known to take the back light bulbs out of it!
Otherthings, they are heavy cars, so likely getting ready for some of the suspension bushes/shocks etc renewing.
Timing belt is 10 years/108,000 miles - the auxbelt and tensioners must also have been done as failure here often takes out the timing belt.
This thread may be useful reading
https://www.volvoforums.org.uk/showthread.php?t=40932