To confirm the registration of an Australian native hybrid & view its composition/progeny: (Database as at 1st January 2020 RHS registrations)
For non-Australian Dendrobium hybrids use the Dendrobium Hybrids checklist here
Sarco. Val= Sweetheart x Heidi ( has 2 hybrid progeny ) registered: 29/11/2008 by Laurent M.J.
Species composition summary:
Sarco. Val = Sweetheart x Heidi = [Fitzhart x Heidi] x [Fitzhart x hartmannii]
Heidi = Fitzhart x hartmannii = [hartmannii x fitzgeraldii] x hartmannii
Fitzhart = hartmannii x fitzgeraldii