Thanks for all the comments, they are much appreciated.
I titled the diorama "kaput", I thought that says it all.
I was originally going to build what would have happened a few hours later when the engineers arrived, but couldn't find enough figures standing around scratching their heads.
I'll have to take some more photos to post them, however I will have to manufacture some more spare time to do this, so it may take a while.
The bridge is made from balsa (bass wood), painted tamiya XF 54 dark sea grey, then airbrushed with a diluted XF1 black (shadow) and XF2 white (highlights), I did an oil wash over it but the wood seemed to absorb the colour without highlighting the grain as much as I would have liked. it was then drybrushed with zink white oil paint.
Tonal values, rust and water runs, and dirt are done with pastel chalks.
Finally a light sprinkling of clay dust was applied to the upper deck and brushed into the cracks.
The sFH18 Howitzer (Dragon) was built straight out of the box
the SdkFz7 (Tamiya) has Fruilmodel tracks, and Eduard photoetch.
The figures were all taken from the (previously finished) spares box
Brett