I've done quarter of a million miles on a mix of fuel from wherever was closest at the time, in a range of cars and never had any problems related to fuel quality whatsoever.

My current car has done 50k since I got it, generally on tesco or Asda diesel.

I can see there may be a longevity argument, although thats tenuous at best, but if your car is dropping into limp home on road fuel meeting uk standards then theres something wrong with it.