Practical classics reckons a category 1 car is worth £2000 and that basically means mint original (not concours) but problem free in every way, they are usually pretty accurate with the values. You are correct on the wheels so instantly it isn't category 1.
Like the way the advert states emissions. Surely with CO of 0.31% all that means is it's running way too weak. Probably should be 2.5-3.5% if correctly tuned.
No mention of full service history.
I'm sure it's a nice little car and I suppose you can't blame someone for trying but price wise that's well off the mark.