I've fitted a low mileage engine I bought of a renault specialist and it has a 1mm wobble on the crank pulley so I called up a mate who owns a 250 and he had a look at his crank pulley on idle, he's does the exact same thing, about a mm wobble, surely that can't be right!!!
It's a dampened pulley so some deflection or minor movement is to be expected. If however you're worried about it, buy a new one and fit it... easy enough job.
