Just wondered what the general opinions of Millers Diesel Ecomax Fuel Treatment were .... if any?

Some swear by it, others say it's a waste of time, but Millers seem to have a pretty good reputation for knowing their stuff, and with the cost of fuel going ever upwards, maybe the V6 fuel pump needing a bit of extra lubrication, I'm toying with the idea of buying 5 litres of the stuff from Wilco direct for £64.49, which should last me about 5 years I reckon Wilco Direct

Question is ... am I wasting my money.

Opinions please ...

Yes.

rotodiesel.

improved cold starting on my car. didn't notice any other difference.

If you really must pour anything into fuel tank, get a canister of decent quality 100% biodiesel and add about 2%-5%, or about 1litre to 3litres per full tank. Just remember to store the biodiesel above freezing, or dilute it 50% with diesel right away.

It'll improve lubricity, increase cetane (ignitability), keep fuel lines clean and will cost less than the diesel fuel it replaces. Your engine is rated OK to work with at least 30% biodiesel content (my 2.5TDI is capable of 100% biodiesel operation)

Many "diesel fuel additives" nowadays are 70%+ biodiesel in content anyway, a lot of them have some propanol (<10%) as well to clean injectors (and prevent biodiesel in the additive bottle from gelling).