? Clerodendrum thomsoniae, Glenbervie House

We came across this magnificent flowering vine in the Conservatory at Glenbervie House, whose gardens were open today under Scotland's Gardens Scheme.

From searching the Web this evening, it would appear to be a species of Clerodendrum - possibly Clerodendrum thomsoniae.

However, both the leaves and the flower colours differ from those that appear in all of the photographs of Clerodendrum thomsoniae that I could find earlier. The leaves of this example are serrated, not entire; the calyx (the sepals, fused here into a single inflated structure) is crimson red, not white; and the corolla (the petals) is yellow, not crimson.

Is there a tropical flower expert out there who can help with identification please?