PowerSwitch

I am sick of my E10 fuel 'going off' so quickly - I use it for mowers and a strimmer.

I noticed that the local Tescos sells E5 fuel .. will this keep 'fresh' a lot longer than E10?

I doubt that it will make much difference, ANY concentration of ethanol tends to attract moisture and spoils the fuel. It should keep OK in a tightly sealed military specification jerry can. In a plastic can or in a vented fuel tank in a vehicle or on a machine it has very limited storage life.

If you drive a petrol car, then I would buy a can of petrol when you need it for the mower, and put the rest in car rather than store it.

If you only use petrol in tools and garden machines, then it might be worth paying the higher price for Aspen synthetic petrol as this keeps better.

I heard someone on a Canadian YouTube video referring to "boat gasoline" which has no ethanol and keeps well. Whether it is sold in the UK I have no idea. Over here you can non-ethanol petrol and I use that for my plate compactor. Ethanol is a hygroscopic substance meaning it absorbs water and forms a miscible solution with it.'

Sta-Bil additive in Oz claims to keep fuel fresh for up to 24 months. https://www.sta-bil.com.au/