I went out on Sunday and as I wanted fuel I went to my goto station which is a Shell, no E5 at all. OK I'll get some from the next one on the way at the next one, none at that one which is a BP. Stopped at the next one along the way and again no E5, this was also a BP. As the light came on, on my return leg I pulled into the last one I tried and had to put some E10 for piece of mind. I just found it odd that 3 out 3 had no E5 at all. These were in SK14/13 post codes.
Slightly different slant, but different countries have different levels of ethanol. I use E5 to reduce damage to old parts in my 50's Italian machines, rather than for the 98 octane level. Italian bikes of that era were designed to run on 1 star fuel. In this country it means using Super Unleaded 98. In Spain both 95 and 98 Ron fuel is labelled E5. In Portugal 95 is E5 and 98 is E10.
That's because the E codes only refer to the ethanol content and are not really tied to the octanes, therefore you can't just assume that E10 or E5 will be the highest octane. In Portugal, it happens that the E10 fuel is strictly tied to 98 octane petrol AFAIK
