Scirocco Central

I've got best part of 3/4 of a bottle of Millers lying round in the garage from when I had a Merc a few years back.

Has anyone used it in the diesel Rocco yet and if so were there any advantages/disadvantages.

Not sure whether to try it since it's already sat there or just throw it away.

Shouldn't do much - diesel purity has come on in leaps and bounds in the last 5 years with the ultra low sulphur fuel grade, can't see your roc getting dirty enough internally in the forseeable to need additive treatment. On the other hand, if your Millers doesn't have a use by date or use within so many months of opening, it can do no harm.