No attachments are allowed on this forum, so grab them from http://www.girlguidestore.ca
by hitting File, Save As and saving the page in a new folder on your hard drive. From there you can test it out...
Here are the files you need:
Nopcat.js and language-en.txt
Do a text search for GST to see the mods.
Tax rate is set at the top part, and the rest of the mods are in manageCart() and checkoutCart().
If you cannot download the files for any reason, just send me a PM with your email address, and I'll send them off.