Rob when it all started and for several years after, we were advised by the FBHV in the "Windscreen" mag that super unleaded at independent stations (Not supermarkets) was still Ethanol free. So I've always bought my bike petrol as advised. But I've noticed for some time now that even these pumps are marked E5. I still continue with it and add a small squirt of Frost's Ethomix. Ron
Since the introduction of ethanol and petrol that goes off quick , I have ran most not all my classic bikes on avgas.
Come the end of the biking year if it has the awful ethanol rubish petrol I simply drain it out otherwise when left it goes off and also will cause damage.
So yes get down to your local airfield and fill a 20 ltr can with avgas. Or failing that use aspen its a little more expensive but will do the same and start 1st time and will last forever like old fuel. But again make sure you drain that awful e fuel out before hand.
