http://www.powerenhancer.co.uk/product.php/3/bg-244-diesel-fuel-cleanerYep, used it on Der Panzer recently, seemed be getting a little sluggish to start, no such problems since & Fuel economy up 1 mpg ish or so. Mine has done 63k.
Just bought another for SWMBO's A3, thats only done 11k but does really short journeys.
My thinking was to keep the injectors nice & crap free.
Worth a punt if ya got £20 spare, cant hurt, seems to get good reviews on many car sites but couldn't find anything official, ya pays ya money .....