Just for the sake of it, here are the 'official' Practical Classics valuations, first for the 280zx 2+2
280ZX 2+2
Concourse/Dealer = £7,500
Condition 1 = £5,000
Condition 2 = £2,200
Condition 3 = £950
I would say this is bang on, although you won't see a 280zx advertised as Condition 3, even if it is!
Now for the 260Z (NB: not the 2+2 but the fhc)
260Z (fhc)
Concourse/Dealer = £16,000
Condition 1 = £10,000
Condition 2 = £5,750
Condition 3 = £3,000
I have not bothered to put the 240Z prices here as there is not enough storage space in the entire 'Cloud' for the discussion that would ensue...
Anyway... if the 280zx prices are bang on and the 240z prices are under, then the 260z 2+2 should be about in the region of the fhc figures above.
Fuse lit... right, I'm off to get a cup of tea, so will look back in on the discussion tomorrow... can't wait! It's better than the Telly!