IBB are right about the launch date, plus if you want a proper answer e-mailing viewer enquiries is not going to get you anywhere. They send out a generic, pre-typed, templated, out of date answer to every question. Your best off e-mailing someone involved at channel 4. Angela Jain for example...
ajain@channel4.co.uk
Who, in my experience replies personally to most her e-mails.