TD5 increased fuel consumption

Have owned a 2000 Discovery TD5 auto for past 2 years.It has been fully serviced by a LR specialist throughout that time ,it runs well and is a first time starter.Recently the fuel consumption has increased from a steady 23-24mpg to nearer 20mpg.I have not changed my driving style,the journey lengths vary but have been much the same throughout (mainly local) and there isnt a hole in the fuel tank!
The EGR has been removed but no other modifications.Has anyone any idea what could be the cause?
Your help would be most appreciated.

i would check the obvious stuff first,intercooler pipes they collapse inside and restrict air flow,AAP sensor in the air filter box,give it a clean with contact cleaner,MAP sensor in inlet manifold gets clogged up with oil.also check the wastegate on turbo see if its not seized up.fuel pressure regulator for leaks.
have you noticed a lack of power,

HTH

Gareth

The very first thing I would do is to put in a new air filter as they are very sensitive to a good air supply. After that I would clean the MAP in the inlet manifold and check mpg by full fill and full refill.

have it pluged in to see if there are any faults and get them to look at the maf sensor out puts

Have you thought about the price of fuel? Or are you possibly using cheap supermarket fuel? I'm not getting as many miles out of my £30 weekly fill. But that's due to less fuel for my money. Also if your journeys are all short and your vehicle is automatic that can have a massive impact on fuel consumption. I recently thought my Disco was getting hard on fuel but when I sat down and looked at it my short journeys had increased.