Not sure how handy you are with things.
Taken from a manual I have.
“Fuel Level Gauge
The fuel gauge is an electrically driven, analogue instrument for displaying the fuel tank contents. The pointer needle is oil damped to prevent impacts on the vehicle wheels, causing deflection of the pointer needle. When the ignition is off, the pointer returns to the empty position.
The instrument pack is connected to two tank level sensors. One sensor is located in each side of the saddle type fuel tank and uses a float operated potentiometer for measuring the tank contents. Each tank level sensor is supplied with a current from the instrument pack. The returned current, via the potentiometer of the sensor, is read by one of the microprocessors. The reduced current from both sensors is evaluated and converted into a signal to position the fuel gauge needle at the appropriate level reading. When the microprocessor determines that fuel tank contents have reached a predetermined level, the low fuel level warning lamp is illuminated and a chime is emitted from the sounder to alert the driver of the low fuel condition.
The following table shows potentiometer resistance values in relation to fuel tank contents and the fuel gauge display. The figures are shown as a guide only because an infinite number of left/right sensor resistance values can be obtained.
Tank Sensor Potentiometer Resistance
Ω Left/Right
Gauge Needle Pointer Position
20 / 20. 0
146 / 121. 25% / 1/4
280 / 213. 50% / 1/2
396 / 323. 75% / 3/4
500 / 428. 100% / 1/1
Two versions of the fuel level gauge are used. Markets with a kilometres only speedometer use a percentage gauge reading marked 0 - 100%, with graduations of 0, 25, 50, 75 and max. Markets using miles and kilometres speedometer readouts use an imperial fraction reading marked 0 - 1, with graduations of 0, 1/4, 1/2, 3/4 and 1.”
I am also guessing you are in London?
If so and you don’t want to tackle yourself these guys maybe able to help. Ido t think changing is a “plug and play” option.
http://www.clusterrepairsuk.co.uk/repair/model/range-rover-vogue-l322-instrument-cluster-speedo
Good luck and keep plenty fuel in it till you get sorted
J