If you look at the screenshot attached - this is what should appear but only does this say once every 20 times! I've found through searching that countless people have experienced this but none of the solutions posted have fixed it for me. I've cleared cookies, tried different devices / browsers as well as checked the 'Allow customers to conveniently checkout directly with PayPal' in the payment settings in Woocommerce.
I can also confirm that the PayPal account (in question) is a business one, that the 'allow guest checkout' option is enabled in the PayPal account and the countries that we've tried purchasing from are UK and Spain. The strangest thing is that it sometimes does work! Any ideas?