Yeah, the fuel gauge seems to be very exponential. So when I stuck £5 in it when I was pretty much running on fumes at inters, the needle moved up to about 1/3 of tank full (about 8mm on the gauge). But when I was nearly full and stuck a further fiver in the tank, the needle only moved about 1mm. Basically when the light come on, get your ass to the petrol station QUICK!!
I think somewhere I've read there should be 7 liters left in the tank once the light comes on, which would give you about 50miles..............but thats lies I tells ya.
Mig