At the end of the day it's your/your brother's decision. All people here are trying to do is make it clear that when you buy a more complex car, you *can* be buying into something that is more prone to throwing problems, which will eat into any fuel savings.
I fully understand this. But I would personally think with such a high annual mileage the risks of diesel ownership would NOT outweigh the benefits of cheaper running costs.
Worst case scenario i suggest my brother buys a petrol mondy, and it goes bang!! Then he's got bills to pay, and his economy is far worse off.
Best case scenario he gets the diesel and no problem occur..
Isn't every car a risk game, obviously the diesel being more of a risk to an N/A petrol car of equivalent age and spec...
The turbo in my Focus ST could go bang at any time, and it's safe to say I certainly don't have the spare cash at the moment to have that fixed. So should I buy a Civic Type R in case of this occurrence???