Kevin,

I think if the contamination is traced to a particular batch of fuel and the oil companies know exactly which outlets it went to,provided you have a receipt you should be able to claim.
It's a bit like whiplash claims after accidents from people that weren't even in the vehicle. The problem may arise with all the people in other areas that seem to be making spurious claims. The BBC showed a map last night where they had received emails people who alleged damage to their cars, and it seemed to be country wide. Let alone some of the weirdos on the Jeremy Vine prog. yesterday.The oil companies may decide to play hardball.
If everyone is successful, compensation could run into millions of pounds. I guess the particular firms in question could easily afford it.

Tom W