If fully synthetic oil is the only type of oil that should be used I wonder why MMC and their dealer network use standard mineral 20/50.
Also after looking at the top link Martyn has posted, by default it looks like I may be onto a winner with the Millers Classic 20/50 as it already has ZDDP in the formulation.
Come MOT time next year I shall see if it has had any detrimental effects on the cats.
