After reading loads of positive comments on Millers' ecomax additive I went for it and added 50mL to a tank of diesel.
After 150 miles the engine noise has changed...for what I think is the worse Sounds asmatic when I floor it past 2500rpm and doesn't sound like the usual woooosh once it gets on the power band around 3000rpm
Mind you...it still goes like a bat out of hell. Should say it smokes the same i.e. an awful lot lol

It's due a full service soon, but it's only done 6k miles since the last fuel filter change