That's the conclusion I'm coming to - there is no reference to landing lights in my schematics, only 'taxying lights'. I've found references to 'landing lights' only as captions to photographs, so am unwilling to admit that as evidence. From the cockpit diagrams, there is reference only to a 'taxy light' switch (forward outer of the right side panel). Therefore, I would say that with the evidence available it's a combined landing / taxi lamp. And from the various photos and the fact that there is only one switch, it's either both sides on or both sides off.