If you reckon your civic is worth £5500, then you'd effectively be paying £6k for a Zed that is barely worth £5k.
It's an 11 year old high mileage import in the lowest possible spec with an auto box in the least sought-after colour. He should be begging you to swap your £5500 civic for that. There's nothing wrong with it as such (although it does not have the stated 310bhp), it just ticks all the 'hard to shift and not worth a lot' boxes. I'd press him for a better deal.
DB
11 year old? Did I fall asleep and lose 2 years of my life