Actually a good question Pete, I'm involved with the airport that is trying to get rid of it, my understanding is for full scale it has a life expectancy in the tank, no diffrent than gasoline. I'm going to say 6 months I may be wrong. After that they are not allowed to sell it as aviation fuel.
We have 1900 litres to remove, the airport is no longer going to sell Jet-A due to reduced jet traffic..(none) except us

the Fuel is less than a year old for and is in a proper aviation fuel dispensing tank and pumping system.
Any other experiences or technical knowlege would be great to hear.
Angus