Thanks for the various suggestions. I've managed to produce a PDF of the original file by printing to file as mg suggested (using Jaws PDF). I've also produced a reduced size of PDF from Xara using 1mm=1pix as Soquili suggested.

I've had no problem with this size of banner in the past. I take it to our local sign printer (AllRound Signs) and he prints them off from a roll at full size - in this case 1745mmx820mm.

Thanks for trying with AI, Albacore - interesting that it doesn't work with that either.

Maybe something for Xara to investigate?

Thanks everyone.