Thanks for the suggestion. AutoCAD2009 doesnt have the R14 dxf option, it has 2007, 2004, 2000 and R12 dxf versions. I have just tried it with an R12 version and still nothing imports.
Clutching at the via CorelDraw straw, I have sorted the scale issue as CorelDraw saves its version of DXF it changes the mm to cm if you don't spot the option box as you do it. Ching the export units to mm means it exports it the right size. That does produce a DXF that will import but there is another problem. The import of the CorelDraw DXF appears to have distorted what should be round holes in to more sort of rectangles with rounded corners. There are distinct flats to the shape although the Cut2D says the X & Y values are correct for the diameter of the holes.
Any more straws I can have a clutch at?[there's no pressure here but there is a steam engine in north wales restored and ready to run apart from the bits