As you've already got the clutch off the bike then you might as well spend £250 for a new basket and plates. The next thing you will notice with a worn clutch like this is clutch slip when powering hard.
Worn clutches like this are very common if the members here are anything to go by. I think everyone must have replaced a clutch by now
The life span does vary from as little as 4000 miles to 14000 miles but just don't expect much life from even a new one. Hmmm - I feel a poll coming on.