Hello mate, this is something I thought of doing but decided against putting in place now because of the number of orders it might create, and the fact that free downloads subvert the order system and I'd need to test how this would function with the user account system in WooCommerce.

There is an action you can use that get's called just before a successful download file is fetched as follows:

do_action( 'somdn_count_download', $product_id );

If you need to access any other data my plugin processes it's all in the $_POST variable, as the download is essentially a php $_POST form request.

There is also the following action for variation download specifically, although I don't actually hook into it for anything.

do_action( 'somdn_count_variation_download', $variation_id, $product_id );

Thanks mate :). I'll give that a whirl.

I'd need to test how this would function with the user account system in WooCommerce.

... can you elaborate on this one for me?

Sure. When an order is created it shows up in the user's purchase history. If they download the same product twice, they will have two orders for the same thing. It might also confuse some systems like refund or support requests.

There is an option in my plugin settings to display the free download history for a user on their account page. No duplications, just all products they have previously downloaded for free and are still eligible to download.