Just double checked my file structure and it was wrong, having read the documentation on Woocommerce page (again) I found that it needs to be like this >
themes/your-theme/woocommerce/single-product/add-to-cart/variable.php
NOT
themes/your-theme/woocommerce/templates/single-product/add-to-cart/variable.php
I copied the file structure exactly like it is within the woocommerce directory and it seems all I had to do was omit the templates folder.