Unbelievably naive question this!
What part of the headlamps do you put the obscuring tape?
The group of Morgans I travel with put it on in approximately the 8 to 9 o'lock position when viewed from the front. Both lights.
However I've come across photographs in Miscellany where it's on the opposite side, 3 to 4 o'clock position. The number plates are correct so the photogrpa isn't reversed!