Using the R1C! you suggested, I did this, which seems to work:

ActiveCell.Offset(0, 7).FormulaR1C1 = "=VLOOKUP(RC3,Lists!R1C3:R99C5,3,FALSE)"

I've looked up some of the elements you used in your answer, like ".address" but can't find good explanations. Anyway, you pointed me in the right direction so much appreciated and rated. Thanks.