Re:

> For his SG tanks Derek uses the pre-scored styrene sheeting, heaps of
little rectangles, just bend off and use. There is quite a range of
sizes
available, so you can use it for pavement in terrain, 6mm bases, for
detailing tanks. Versatile stuff and looks a charm took.
>
> (I will also apologise it its already been mentioned and I wasn't
paying
attention!)

In the States they can be purchased at most model railroad shops. 
Typically
they are listed as polystyrene "tiles" or "side walk."

ias