Ok I don't want to put in too many details in case I get identified and I'm too lazy to name change, but I hope I will be able to get some advice anyway.
Would you speak to your boss if members of your team were complaining about someone else the same level as myself who doesn't appear to be overly busy ? Up until now I'm thinking no, because its none of my business, but now it is going to impact my area and I don't want my team to feel they raise concerns and then I do nothing about them.