I see that Panglobal Plants also sell it, indeed in 2 forms. They note that it does very well at the Hillier Gardens at Romsey in Hampshire.

Also I noted on their blog that in Nick's recent visit to Manipur he spotted a similar but different Cornus, previously wrongly identified as C capitata, growing there, but he doesn't seem to be growing it, at least not yet.., No Whiteys since Kingdon-Ward – Planthunting in darkest Manipur | Pan-global Plants