Disco 300Tdi 1996 Further to our discussions some time ago, I have now blocked the EGR valve - a £2 coin fits perfectly. A bit of firegum should stop it rattling if it does come loose, but it's OK so far after about 100 miles.
The resulting cleaner air has allowed a further quarter turn tweak on the main fuel adjuster with the result that it pulls better from low revs, is smoother at high revs and has a freer, more powerful engine allround. I have been getting 27 to 31 mpg, we'll see if that gets better still. TonyB