Right, for what its worth mate, I have a 99 V6 that I bought about 18 months ago that had done 69k for 3 grand which was still probably too much in retrospect. I have since spent the same again on it. I reckon his price sounds a bit high to me, it all depends on the work it has or hasn't had. A good one that's been loved is worth the upfront cost rather than a cheap one that needs loads spending on it
I would check the clutch bites well, under load - if it needs changing that's a 600 odd quid job.
Check the suspension. If it its had any work, that's positive- and if any of the bushes have been changed. Drive it and listen for any squeaks. Bushes are a common weak point on them Spring pans (look like a saucepan and support the rear springs are prone to failure and they are about 200 quid from memory)
Body work - rear quarters are prone to dings and very hard to get rid of so look carefully at those and check for any overspray surrounding the panels to see if its had any paint.
He states that the belts were changed at 38k, and the car has done 53k. I'd find out when they were done. I have just had mine changed, and they were very thin and glazed. They had only done 23K since the last change but that was something like 5 years ago. They had clearly gone through many heat cycles even though they hadn't seen many miles! Check when they were done and if the tensioners etc were changed at the same time. They may have also changed the waterpump. I believe the later ones suffered from impeller failure and the earlier ones less so, and therefore a pump change probably should have been done at the same time.
Check it comes up to temp (90 ish) quickly and stays there.
When did it last have an oil change and filters? Plug change? They are about 60 quid a set from memory...
Interior looks pretty original and clean, bolsters look strong. Check door cards where the seatbelts are, sometimes they punch a hole in them if they aren't fully out the way when the door is closed.
I'm sure there are others on here who will have much to add (and any corrections!!) but the above are the bits off the top of my head that have cropped up on mine thus far. I reckon the golden rule is that its better to spend on a good one that you know has had much of the work it needs done to it.
I reckon 4750 is probably a bit high in any event but if its had loads of TLC and much preventative maintenance (if it had I would hope for better description in the ad??)that's better than buying a cheap one that needs much TLC like mine did!! Good Luck and let us know how you get on