Ok...

For EuroFleet and WorldWide, we have:

Cabin Service Director
Purser
Main Crew

It can take many years to progress upwards from Main Crew.

We do use crew to improve the product, and not just CSDs or Pursers. There are a group of crew, a mixture of grades from all fleets, who meet, I think every 6 weeks, and discuss changes to the product, how improvements could be made, what can be changed without actually changing what customer are offered etc... I don't believe there is anything offered in addition to normal working time etc...