Integrate WorldPay with static PHP website

General information for the website: We offer short term accommodation
Kind of development: Customization of existing website
Description of requirements/features: I want to have an online payment page setup which will connect to a WorldPay account; something similar to http://www.woolleybevis.com/about-us/online-payment/online-payment-invoice-settlement.html

The website to which this form will be added is a static PHP website built on XHTML & CSS. I don’t require major styling done. The form can even be in a table instead of div tags and unordered lists. I will take the code of the working form from you and will then add it to the website myself. I will take care of the styling too.

The form will require the following fields:

- Full Name (textbox)
- Reference (textbox)
- Payment Type (combobox with 3 options: Rent, Deposit, Deposit & Admin Fee)
- Amount to Pay (textbox)

All fields are mandatory. Error messages will be shown upon form submission if the mandatory fields were left empty or incorrect values were entered.

The error messages will appear at the bottom of the form and the fields will appear with a red border as can be seen on http://www.woolleybevis.com/about-us/online-payment/online-payment-invoice-settlement.html

Customer has to pay a minimum amount of 5. The currency will be GBP.

Upon successful submission of the information the user will be taken to the WorldPay payment page to make the payment.
Extra notes: