If you have signed up to Ultimate Volt then it should be included reading this,
Sky UHD: Sky Cinema and Sky Entertainment UHD requires a V6 or Virgin TV 360 box and a 4K compatible TV/device with HDCP 2.2. Up to 4x the clarity of standard HD content: based on comparison of HD (1920 x 1080 pixels) versus UHD (3840 x 2160 pixels).
New Ultimate Volt customers: Sky Cinema and Sky Entertainment UHD included with bundle. Subject to 18 month minimum term. Existing customers renewing Ultimate Oomph bundle: Sky Cinema and Sky Entertainment UHD included. Subject to 18 month minimum term.
£6 a month for existing customers of Maxit TV (Fullhouse/Bigger Bundle/Ultimate Oomph) packages. 30 days’ notice required to remove Sky Cinema and Sky Entertainment UHD pick. Prices may increase at any time during the contract.
This price is on top of your existing Virgin Media cable services monthly subscription cost. Service usually upgraded in 48 hours, but in the case of exceptional services may take up to five working days.
That's on this Page in The legal stuff under TV.