I have my application working fully on my development machine and storing data all okay on a SQL 2008 database, how every when I deploy the application to my server, which is running SQL 2008, and the model is stored in the database the date fields do not accept an English date format.
e.g.
13/08/2009
fails
Sounds like you are running with a different culture on the machine you have deployed to, where that date format (US) is not valid. First place to look is the culture set in the Windows Control panel.
If you can't change the machine settings in ASP.NET you can do this through the Web.config file.
CodeProject has an article describing one way to do this for Windows forms.