There is a program called view companion that converts plt's to anything, also scan2cad which converts raster images (tiff or mono bmp's) to dxf.
So in theroy you could save your pdf as tiff, and use scan2cad to convert to dxf.
to get pdf to tiff, I would take good quality full size prints, send to printers to scan in to tiff, then use scan2cad. sounds like a round abt. way, but it's only 90p for A0 scan.
I think scan2cad is abt. £50 - £100 online..
