A quick google found this
http://www.oilem.com...-diesel-fuel-2/
Quote "So yes, premium diesel is better than standard diesel. But is it worth its higher price tag?
On that matter, we are not so sure. The main issue is that premium diesel fuels could be so much better considering the significant extra cost per litre. The additional detergent currently included is still barely enough to retain a clean engine on most fuel systems and engine types, and fails to actively remove existing deposits. Unfortunately, we find that diesel vehicles that solely use premium diesel fuels continue to accumulate deposits. Not so much in the fuel system, but in the combustion area, emission components (EGR, DPF), and intake manifold, intake valves, etc. Using a premium diesel will undoubtedly delay the formation of carbon deposits in these areas. But don’t expect miracles in regards to cleaning performance. The increased bio-diesel percentage contributes to an increase in fuel system contamination, biological degradation, and carbon build-up. Unfortunately, current fuels do not do enough to address these issues.
Please note, in the manufacturers’ defence, there are regulatory considerations, such as the outdated BS EN590 specification, that control what additives can be included in fuel. But those regulations are irrelevant to whether premium diesel, as it is made today, is a good value for the price you pay at the pump.
So if premium fuel isn’t worth the extra cost and standard diesel is lacking,
what should you do? We suggest adding a high-quality diesel fuel conditioner with combustion catalyst technology to standard diesel fuel. Doing this will generally create a fuel that will outperform a premium diesel and be more cost effective, per tank. We have substantial testimony, as well as research data, that supports this. More complete fuel conditioners contain effective technologies to proactively clean and remove existing deposits, lubricate the diesel pump, remove water, prevent fuel degradation or contamination, lower emissions, improve performance, increase MPG, and so on.
It is simply a case of weighing the benefits of premium diesel versus the additional benefits of a fuel conditioner, while also considering convenience and cost."
My bold underline - their suggestion is what I do.