Frank
I dont really know what it is for sure. Looks something like a Impatiens hawkerii meaning a NG hybrid. If it has whorls of leaves it may be hawkerii. It is not hochstetteri or sylvicola these two are somewhat similar and have the same kind of habit like burtonii. What ever it is I sure would like a cutting of it. It maybe something total different, there are some species that have similar flowers but different habits than burtonii. Very nicely grown plant you should be proud.
Derick