Its listed in the Lucas bible for 1957 as an E3L 20035A for the Tiger 100, 110, TR5 and TR6.
be the same for 1959 ? Don't know how far back these go, this was just a later version of what was before for quite some years ? It has the gear on the end, and looks quite similar to the Norton one, and magdyno generators, although different teeth counts.
Be aware that a fully charged battery can give an hour or 2 of good headlights, and this can be enough for road use if you don't actually intend to ride at night ? Contant loss lighting...
Cheers.