Like its relative Medinilla magnifica, the inflorescence are pendulous while the wild species in a previous post are errect. Another obvious difference is the leaf shape, and possibly the leaf venation of which I was unable to observe in detail due to inaccessability of the wild plants.
Addenda
As pointed out by Mr Luther which I later verified from a quick search, Medinilla scortechinii has orange inflorescence so this plant was obviously mislabelled in the garden. I do not have any keys to Medinilla identification, so I can only offer possible IDs - pendula and speciosa being two of them.
Cheers.