This is my first time round using Umbraco and I have created Document Types / Pages using the wrong naming format and now this has transpired into my page URL\'s, for instance <
Unless I'm very much misunderstanding your issue, you should just be able to change the name of your page and republish. This doesn't need an additional field, just change the value in the "Properties" tab and republish the page. This will automatically change the URL of the page.