As Gaz said, I don't think you'd be too vulnerable to spam unless you actually had your email address as a mailto link on any of the webpages.
Although, of course, you may also simply not want people in general to know your main username, especially if it is your actual real name. I believe ntl Tech Support can change the "name" for the webspace to something else, i.e. link it to a different & not so identifying ntl email address rather than one containing your name.