Excise duties are not based on values but on quantities of a commodity and therefore do not vary unless amended in the budget. The rate I quoted was the excise rate according to the HMCE website and is the full excise duty rate for Avgas, all of which is reclaimable as drawback. There are other taxes on Avgas - namely import duty (if it comes from outside the EU)and the dreaded VAT both of which are value related as a percentage.
Confused ? You are now !