PS The price per litre of AvGas will be £2.28594. Probably the most expensive around.
Here in Holland we pay more.
At EHLE for example we pay just short of 3 euro's (£2,38) per liter.
Lelystad Airport Fuel info in Dutch
I do hope that you can solve this issue with the supplier. AvGas is a very slowly dying fuel type. We should be shifting to Diesel and Mogas alternatives.