Hi Rob,
my Inkscape is down at the moment but I looked at your file with Xara and Corel Draw.
I opened it with CD4 and it appeared OK. It is an Antarctica map with the graticule overlying it and numbers around the outer circle?.
Xara DP6 could not open it.
I then used DocsPal to convert the file to map1.pdf. Then it opened in both CD4 and Xara.
You will probably have to do some recombining to get back to what you want since the bits are all in one layer at present. However there should be no trouble in adding text to a new layer.
I am using Win XP. Let me know if you want a pdf.
cheers, Erik