Hi Lucinda,
That's great news! So, to help here are the answers to your questions....
1. Yes - this date has been confirmed to operate.
2. There are currently 11 confirmed travellers and one provisional traveller. Ages are from mid(ish)-40s through to early-70s and the split is 4 men and the rest women.
3. No, you do not have to purchase your visa through Just You, this is an additional service that we provide should customers wish to use it. There is a section about Passports, Visas, and health requirements in the booking conditions which you can view here:
http://www.justyou.co.uk/customer-support/booking-conditions/ (the bit that will be relevant is section 13)
If I can be of any further assistance, please do not hesitate to get in touch.
Kindest regards,
Julia