Thanks for your quick reply.
No this is not my own site, which I have hardly started yet.
This is the example site, BubbleUnder.com used in the Sitepoint book. I have worked through the book creating the site as suggested. In Chapter 7 after creating a good looking contact form for the BubbleUnder site, the reader is asked to register with Freedback.com, create a form with them, then copy and paste parts of the code they create from your form questions, into the contact html for the BubbleUnder site. When I did this and saved my amended contact html, I then opened the contact page to find that the form had changed radically. As I said in my first post, it is as if the css has been lost from the form. The rest of the page is the same as before, it is just the formatting inside the form. I then filled in imaginary answers to the questions on my form and submitted it. This worked fine and I soon received an Email with these answers on it.
I hope this clarifies my position. Many thanks. John