ZfD4 (see first word of original post!?)
I've applied all the latest patches up to patch 3 but didn't work.
Actually read somewhere about it being caused by having a base image that was taken from a manufacturers (Dell in this case) rollout image.
I FDISK'd and rebuilt the machine from scratch, then took the base image from it, I've been able to push the new base image out to other machines OK now.