Spot the difference

This is the forecourt of the sales department of my local petrol station, Kirkby Motors. (They don't sell the cheapest fuel around but I go there because I want them to stay in business!) (And they sell logs, kindling and coal.) (And Costa coffee.)

Normally, the range of cars is the hotpotch you might expect: different models of varying shapes, colours and sizes. Today, though, there were these four vehicles, with similar number plates and just a fifty quid price difference between each of them.

I wonder what justified the price difference. I could have jumped out of the car to take a look but in was raining and, you know, cars.