UncleD....Your magneto has the later screw on cap, so I would expect it to be a later unit and have the later steel points as in Julian's post. Your points are the early type and may be fitted with the later retaining bolt (no taper under the bolt head). If so this is incorrect for your points, allowing a slight sideways movement from centre as the bolt is tightened.
Easy to check, undo the bolt, have a look and maybe wiggle the points off with some needle nosed pliers. They locate on a small keyway, so you cannot upset the timing as they will go back in the same place. The points pivot will be self evident, the heel of the points arm is the hard plastic brown bit that bears on the cam. Your points look correct for the direction of rotation. The bolt should have a taper to match the one in the points plate.
The scabby bolt on the Auto Advance Unit (ATD) is supposed to break the taper as it is unscrewed from the magneto armature but is rarely successful, and more violent methods have to be used. Yours looks like a standard bolt crudely modified to drive the Tacho gear. Make sure it is tight before start up, otherwise the ATD will move on the smooth armature taper and the set timing will be lost.
On a twin cylinder maggy, the pick up slip ring is not continuous, and the cylinder which fires will be the one with the brass contact strip under the pick up brush when the points break. Easy to check, set the maggy to fire, remove the rearmost pickup and look down the hole with a small mirror.
Swarfy.
