Just installed module and seems to be working great!

I did notice one error though , on the checkout page when you want to choose how to pay , it says

MODULE_PAYMENT_WORLDPAY_TEXT_TITLE.

not really an error but thought I would point it out.

Fixed this by going to - www/includes/languages/english/modules/payment

//define('MODULE_PAYMENT_WORLDPAY_TEXT_TITLE', 'Credit Card via WorldPay');

Simply remove the slashes at the start. :)