One to guess!! ?

[Chad]

You are right with Thunbergia gregorii.

Has anyone overwintered it outside?

Chad

[Chad]

This is a Rostrinucula.

When I tried to 'key out' the species it didn't quite fit either of the two in the genus.

It is trading under the name Rostrinucula dependens.

And it looks like it may move from 'niche' to 'mainstream' horticulture.

Chad