As I said if I had to pay 1k more I would end up with the same car with 40k less miles and a Citroen dealer warranty for a year.
Not looked into exact figures but I doubt you'll be able to do the swap for £1k.
First of all you'll only be getting part-ex money for your current car, so somewhere between £1k to £1.5k less than you could sell it for privately. That's before the dealer knocks off money for the scheduled maintenance which is required.
Then bear in mind you're looking at buying a car which has a higher initial value anyway due to the lower mileage and the extra cost associated with buying from a dealer (that years warranty they give you isn't free after all).
Look at it from the salesman's point of view..would you be keen to do a deal with someone who wanted to swap your 60k mile car for one with 100k miles? Chances are at that mileage he'll probably send your car straight to auction so he'll want to make sure he's getting enough of a profit out of the deal to make it worthwhile.
I'd say you're probably looking at a couple of grand to replace your perfectly good car with something identical but with lower mileage. I really can't see it making any financial sense whatsoever because you'd be paying a lot of money for what really is very little gain
