This was discovered after consultation with a colleague who shall remain nameless but, well, nailed it basically. The answer appears to be: An example command line for running the script was written in a word document. The "Autocorrect" (sic) feature in word replaces a normal dash at least as I know it with the character Jeff Epler showed above, u'\N{en dash}' which is a nice big long dash in the Arial font.
If you cut and paste that onto the command line, bad things can happen although when I do this on my machine I actually get a "u" with an "^" on top. For whatever reason it must have looked ok on my colleagues machine (or possibly this isn't the answer but I seriously doubt that) and when he ran the Python script things went awry. Thanks Jeff (and nameless colleague). And beware Word autocorrection. -- http://mail.python.org/mailman/listinfo/python-list