Apart from the headlights, all the light bulbs in the three-wheeler are LED from the factory (in mine at least), so I assume this is in fact a headlight question.
Rockabilly John - are you asking about the marker/side-light bulbs in the European headlamps? (The US ones don't have these)
Right, and I now understand that all bulbs exept headlamps are LED. But the headlamps cannot be BA15s? I am confused, and I seem not to be the only one. Perhaps the thread starter could specify the problem a little more?