A welcome confluence of circumstance.
A BBC2 broadcast of Covent Garden's Hänsel und Gretel sometime over the Christmas period (date not yet known), plus the start of live online streaming for BBC1 and BBC2, means that you should be able to watch Hänsel und Gretel online.
Depending on which performance they choose to film, the cast includes Angelika Kirchschlager and Diana Damrau, or Alice Coote and Camilla Tilling as the children, with Thomas Allen or Eike Wilm Schulte and Anja Silja or Ann Murray in support. Colin Davis (in possibly his last ROH show) or Robin Ticciati conduct.
The Royal Opera House website may have further information on its TV page here at some point.