Hi John
I use supermarket petrol in my 2005 XJ and my 2001XK. Touch wood I haven't had any problems but it's too early to say what they will think of the E10. On the other hand my 1952 AJS was running like a bag of hammers and sounded like the big end was knocking. After much investigation I was advised to use decent petrol and an additive which I used anyway and it was like a different bike. I wonder how the old AJ would take to E10.😕.
Pete
PS
At 72 I'm wondering if anyone who isn't on a pension runs one of 'our cars'