OK, I have found a solution that works for me, but it does require a bit of simple coding.
Firstly, you need to create a child theme, as any changes you make will be lost if there are any woocommerce or theme updates. It's a fairly easy thing to do, and there are plenty of youtube tutorials on the subject. Once you've created your child theme, make sure it is activated in the wordpress theme admin (you will need to keep your original theme installed, but don't activate it).
Second, you need to copy over a file from your woocommerce folder to the child theme. The file you need is called variable.php and is located in;
wp-content/plugins/woocommerce/templates/single-product/add-to-cart
Paste this file into the following folder (you will need to create the folders if they do not exist);
wp-content/themes/your-theme-child/single-product/add-to-cart
Next, go open the variable.php file located in your child theme with a code editor (most hosting services allow you to do this within their control panel). Locate the following line of code;
<?php foreach ( $attributes as $attribute_name => $options ) : ?>
Directly under this line, paste the following piece of code;
<?php
if ( $attribute_name == 'Ships From' ){
continue;
}
?>
Then save the file. This is all the coding you need to do.
What this will do is keep the attribute live, but hide it from view. You will not need to change or remove any of the attributes or variations in your product page, but you will need to set your 'Ships From' default setting in the variations to the country of your choice (e.g. China). Customers will only be able to see and select the other options that are available (e.g. size, colour, etc), but the 'ships from' option will be hidden from them and will be set automatically when they add to cart.
Because we are not changing any of the attributes or variations in the product's admin page, all stock and price changes will be updated automatically when synced.
I know it may sound a little daunting, but this is a one time job that will save hours of tweaking and playing around with attributes and variations for every single product. It has definitely worked for me.
Hope this helps, and let me know if there is anything you don't understand.