adding text to checkout_payment.php

[schoolboy]

It's probably this one:

includes/languages/english/modules/payment/paypal.php

(Around line 22)

define('MODULE_PAYMENT_PAYPAL_TEXT_CATALOG_LOGO', '<img src="' . MODULE_PAYMENT_PAYPALWPP_MARK_BUTTON_IMG . '" alt="' . MODULE_PAYMENT_PAYPALWPP_MARK_BUTTON_ALT . '" title="' . MODULE_PAYMENT_PAYPALWPP_MARK_BUTTON_ALT . '" /> &nbsp;' .  '<span class="smallText">' . MODULE_PAYMENT_PAYPAL_ACCEPTANCE_MARK_TEXT . '</span>');