My 1.9 TDI estate runs @ 40 mph with out my foot on the pedal,the car has only done 600 miles from new.

I am told by the dealer that this is a feature of the diesel VW's so that you do not stall & can creep in 1st gear without using the accelerator pedal.

When I take my foot of the accelerator between 900-1300 rpm the revs remain the same & the car does not slow without use of brakes & gears.This is very disconcerting when coming up behind traffic & releasing accelerator with no retarding effect from engine.

Having previously driven diesels fitted with exhaust brakes I am not very happy.

Advice welcomed

I find mine runs at about 25 up hill to 35 mph down hill.

Actually, this is getting a touch off topic; I honestly think there's something wrong with Grafter's car's anti-stall or throttle position sensor if it's trying to hold the revs anything over idle.