[Cartmaster]

Although I think I can see some marks on the crank, It is very rare for these cranks to get below spec. The aluminum rods however do wear, particularly if the oil is not changed regularly. At this stage I would be tempted to get a new set of rods and with a light film of oil applied, fit them and check for any play. If it is minimal I would then try them and see if the engine runs quieter. This is just an inexpensive experiment and as you say, it has been running fine so far as it is. If however, you still have some slop, then a new crank if you can get one is going to turn this into an expensive exercise.