[13hunteo]

Cries in UK $8 a gallon

[loeg]

Your gallons are a bit bigger than US gallons, but not 2x bigger.

[rb12345]

Assuming US gallons, $8/US gallon works out as £1.60/litre. That sounds about right for current UK prices, depending on what and where you're buying it. (Yes, fuel is expensive here compared to the US; that's largely down to fuel duty and taxes.)