This turns out to be a bug with the Woocommerce PayPal Payments plugin which the hosting company has documented for you below:
PHP Fatal error: Uncaught InvalidArgumentException: PayPal order ID not found in meta. in /home/dh_5wkg63/the8tracktapestore.com/wp-content/plugins/woocommerce-paypal-payments/api/order-functions.php:38
Should be noted that the several orders that have produced this error used credit card payments rather than PayPal payments from customers.
Is posting this here enough to get the bug fixed? Or do I submit elsewhere please?