I'm just giving an opinion. If this was a 'for sale' thread, I wouldn't comment as I don't think that's right, but as it's in discussion, i think it's eligible for critique.
I think £600 is about right. They're pre facelift so have the ugly Seatbelt holders and grey bits, have bolster wear/saggy leather in places and aren't heated.
I have no problem with them being manual. I actually think the electric seats (which I have) are pretty much needless as they take far too long to adjust.