Automatically include users email address in the contact email field on job contact form

Hi,

I want to automatically include the signed in users email address in the contact email field on job contact form.

For example on http://twid.simplecsr.com/demo/job-contact/?contact=clean-the-kitchen-2 the page looks like this.

I would like the email field to show already populated with the registered email address of the user.

Many thanks
chris