Hi Pat - thanks for your reply.
Apologies, I should have been clearer. I used Polylines to create the 'roof' sections, and once the shape was completed in VW it filled and became (what I'd call) a surface. The lower section was made by drawing a rectangle from the basic tools palette, and using 'push/pull' to extrude this. The whole time it's a 'filled' shape, which I take to mean a conection of surfaces.
Once opened in Illustrator, and AutoCAD, I get the attached. Here in Illustrator to demonstrate what I mean, I've 'exploded' out the roof sections and given them a fill (they imported with no fill). These imported as surfaces, albeit in the wrong order front-back (I would have to use the 'arrange front/back' tool to correct this, which isn't feasible on a more complex drawing, this is just a test). The lower section imported as a grouped selection of single lines. There is nothing here to fill, and each line would have to be manually connected in Illustrator, which again isn't feasble on a larger drawing.
I should also note that I'm exporting as a 2010 DWG, and my online research told me anything newer and Illustrator would not read it. As I'm having concurrent issues in AutoCad as well, I'm pretty sure it's something I've done wrong wither in my VW drawing, or when exporting. I have tried playing around with basically every export to DWG setting there is to no avail.
Any further help gratefull received.