I think there are 2 schools of thought....I'd personally go for the cheaper option...I've never really been sucked into the 'years' thing especially when it comes to a used car....mileage, condition and service history are my main criteria
1/ its within your budget (always stick to your budget) ...no doubt there's some bartering to be done to get t even cheaper...
2/ I suspect you're planning to own it for a few years...so really in 2012 (for example) the difference in value between the 2 cars is going to be negligable if they had similar miles...afterall in a few years ..whats gonna be the difference in a 11 year old car and a 9 year old car to another buyer if you're selling
3/ If all things are equal and they have both got good service histories, have recent NCTs, in good presentable order....I'd tend to go for the cheaper one....
In the current climate you can barter hard and if in your mind you want the newer car then I guess it doesn't do you any harm to put your offer of 4000euro in and see what they say