Hi,
Thanks for your help Bobi.
I got a reply from the VW tech support company here in the UK. They suggested that "The drawing is too far away from the internal Vectorworks origin. To rectify this if you go to Tools > Origin > Center Drawing on Internal Origin. This should resolve the issue."
I did this and it did resolve the problem, however, I do think that there is a bug in the file as I still had to remake some of the hardscape areas to get them to show but it's all sorted now. Thanks again.
Jane