Cookies not retained when using cookie container

This is actually an issue with the CookieContainer in .NET 3.5 which Microsoft are not going to fix, but is fixed in .NET 4+.

See https://connect.microsoft.com/VisualStudio/feedback/details/541197/cookiecontainer-domain-handling-issue-net-2-0-3-5.

There is a work around which I have added to my "modified" version of this code.

(We're stuck with .NET 3.5 due to SQL Server Report Services.)
