Hi Prof, ...There is a Bowden lever on the LH side of the cockpit (Photos later ) and this , via cables , controls the ignition advance and retard on the magnetos , positioned at the rear part of the motor , just ahead of the propellor . ..As per the original drawing , the plates are screwed , close to the lever , on the inside of the pilots cockpit cowling , Fwd to " Retard " and back to " Advance "...Seems the wrong way , but thats what it says ! ....
BTW , I could supply you with a spare " Retard " plaque !

(Just couldn't resist it also!) ...Just kiddin'
Regards John
PS..I've often seen it , but just can't figure out what LOL stands for ???

...I presume that you were not making "Advances " to me!