We would like to add a Shopping Cart Rule whereby the customer adds a coupon/voucher code to the checkout page. And this would remove the TAX from selected products, these products would be Tax free. I have worked out that I can apply a % discount, to the including tax price etc, but that does not make the product Tax Free, just cheaper. Any ideas?
If memory serves me correct, if you want a product to be tax free, you will need to set the "Tax Class" on the product to "None". This can be found in the Product -> Prices tab.
If you want to apply this to certain customers, you could use something like Enterprise's customer segments module which hooks quite nicely into The promotions engine.