Disco 2 V8 Fuel Consumption

Hi, I use my 2001 4.0 V8 ES Auto everyday as a works vehicle, being fed up with vans I bought my disco and stripped out the back seats fitted some storage bins and racking and it's great for what I do. The car runs faultlessly but I can only get 10mpg no matter how I drive it, whether on a run or around town. It has an outstanding full service history, new leads, plugs and filters recently fitted but still only 10.
The MOT chap said the emissions were 'spot on' and all the brakes are free, I don't drive fast or accelerate hard and the car isn't in any way overloaded.
When the fuel light comes on I put 10 gallons in (46 litres) and it will do exactly 100 miles before the light comes on again.
It's not a major issue as I love the car but with fuel prices starting to creep up again if there was anything I could do or check to wring out a little more economy would be great. I tried overinflating the tyres but that just destroyed the ride quality.
Any suggestions would be most welcome

Check the fuel consumption in the excepted way, filling up the the brim or to the pump cutoff , set the mileometer to zero, drive till there's half a tank left and refill as before and then do the sums. If you using pump cutoff method then return to the original pump, as I understand there can be a difference between pumps... maybe, maybe not?

The fuel light is possibly only accurate when there's a steady illumination, when it first switches on then we go around a bend and it goes out. I can travel 15-20 miles with it doing that then it goes steady, so two gallons left time to start looking for fuel

My V8 does 14mpg with everyday use and 22mpg on the highway with not too fast motorway driving. Perhaps let someone else drive yours to check if it's performing satisfactorily. (I'm in Sydney so can't help there!) Ambrose.

Agree with above, you need to have a better method of checking your mpg than over only 10 gallons and what you think of as not fast or hard driving might not be what others thinks of. However if you do that and are still only getting 10mpg or so then you need to check a couple of other things: What revs are you pulling during the majority of your driving? In other words, is the Autobox not changing up or slipping? I can't tell you what I'd expect as my Disco's a manual but sure someone will be able to give you a breakdown of speed / revs.

Also remember that the Bosch engine management system overfuels the engine to cool it down so whilst the MOT guy might not see a problem with emissions, if for some reason you have a sensor failure somewhere or other ECU fault then you might find the engine dumping fuel into the cylinders to keep them cool during normal driving.

All of my V8's (on LPG) always return around 13.5 - 18.5mpg regardless of what driving conditions they're in so I'd expect you to get an easy 30% improvement if the vehicle was running properly, should help at the pumps.

I'm only getting around 10mpg across petrol/lpg although I do have a pre cat O2 sensor down at the moment. Having read various threads I'm about to pull out the NGK LPG1 sparkplugs and replace with standard NGK BPR6ES gapped to 0.7 to see if that helps a little.
Not too fussed though because as LPG is only 46p a litre round here and diesel is 121.9 in my head its doing 25mpg