Uneven shadows in renders for animation

I have produced a rendered animation of a lightbar product with a couple of static point lights inside with rotating reflectors throwing the light out in a circular movement which produces the flashing. But the shadow of the unit on the roof of the vehicle (or is it the reflected colour of the plastic base on the metal roof) is very uneven.

This is not too bad when the view point for the animation stays stationary. But when I do a version with a moving camera, the aritfacts change with each frame and I get a very distracting movement under the product.

I have tried changing the settings on both the lights in Photoview (shadow quality) and in Solidworks (specularity and ambient).

I have changed the roof appearences (specularity amount and spread, reflectiveness,blurry reflections, double sided illumination off etc).

But I can't seem to get rid of it. Since I have 300 frames, I don't really want to individually post process each one!

Any one have any thoughts please? Many thanks.

Dell Precision T3500

Win 7 64bit Ultimate

SW & PV360 2011

SolidworksPhotoview 360