From my understanding of the system, bugger all oil gets there hence the Nipple!
Bash it in and be done.
Tsk. You welsh rough boys
When you remove the rubber seal from the output shaft you'll see an inner shaft sat inside the end of the outer needle roller and hopefully grease will be present. These two shafts both rotate but at different speeds. The inner needle that you can't see stops any transmission oil reaching the outer bearing, as the bike leans to the left on the side stand it will never find its way there during storage. Once the grease dries up that outer needle roller will turn to dust causing a complete engine strip and a bill for about 2 grand. TAP the ally lube plug in carefully. Once its started use a suitable sized socket, only tap in until flush with the end of the output shaft. Do not recess it...........Dave