Hi Paul,
When you get the work done could you check for tightness of the crank nut and condition of the plate washer (corrosion, wear) before dissassembly?
At a push it may just be that the nut needs tightening and washer replacing.
At c60,000 miles I needed a new crank as well as r/h main bearing (under warranty) apparently due to corrosion??!! At c90,000 miles I needed to change just the r/h main bearing (diy) and although there was again signs of corrosion the main cause of wear appeared to be due to the crank journal spinning inside the inner race of the bearing.
Crank nut not tight enough?? Torque spec for current Tenere is considerably lower than that quoted for earlier/old school models.

Look forward to your findings (hope it's not too major/costly).