The code is ready, and functional.

You'll need to specify both the user/vendor/partner/password section, as well as the API user/signature/password settings.

Then you'll need to set both modules (express checkout and payments pro) to Payflow-UK.
And both modules to "Live" (not sandbox).

I suggest enabling debug log-to-file, and mark your /includes/modules/payment/paypal/logs folder writable (777) using your FTP program. This way the logs can be reviewed for more detailed understanding of any problems you might be encountering.