Creating LDraw Duplo Models

I got an email from someone in China asking if I could make my 3D model to ldr file conversion work for Duplo bricks - he'd already had a go and included some .dat file for 1x1 and 1x2 Duplo bricks but I needed to tweak the code a bit to make it work - with Duplo, the models are less likely to be physically possible to build (at least with the bricks he initially wanted to use - 1x1,1x2,2x2,2x4) but the code tweaks were less complex than I expected.  A couple of examples of Duplo models built using my revised script below: