An anonymous Google doc is doing the rounds of agencies in the US, giving details (submitted anonymously) of agency salaries.
With details of sex/sexual orientation and years of service which, to no-one’s great surprise, shows that white males of a certain vintage generally earn more.
Creative directors/senior creatives are pretty well paid $100-200K as are account directors and new business mavens; some “analytics” people are pulling in more, which shows how the business is changing.
There are some numbers from outside the US but not enough to be al that representative. Maybe someone in the UK can have a go?