leather missing from nob is VERY common - mine has gone and its done 43k miles
TBH, looks very good.
Check it drives nice.
Check for suspension knocks.
Check noisy wheel bearings.
HPI check on phone.
Check cam belt is done (possibly x2) and doesn't need doing again in the near term.
Check interim oil changes have been done (min every 6months on car with this many miles)
Jap engine should be rock hard
Check manifold for leaks and gasses (you will be able to smell)
Check any bills and paperwork (don't be shy rummaging through)
Ask why selling.
Go in at £2500 and you will have a bargain (IMHO)
JJ