I am trying to apply UK VAT 17.5% onto my store but it doesn\’t work at all. I have added new tax classes etc in Sales > Tax etc but it doesn\’t apply the 17.5%. The only one that works is the default US-CA one.
We need to confirm you have actually selected the right Tax Class for the products, then screenshots of both Sales > Tax (all sub areas) and System > Configuration > Sales > Tax
It’s such a broad, complex, far-reaching topic that it’s hard to discuss without seeing what you’ve done so far.