All is working fine, and we receive a cart ID back from the response like this:
Next we want to send the user to their /cart, not the checkout flow.
I can only find documentation to send the user into their checkout flow using this method.
I assumed that with the Cart ID we could somehow use Cart Permalinks to achieve this, however this feature is focused on actions like adding products to the cart, applying discounts etc. None of the options allows you to take user to /cart via the Cart ID.