Have the people moaning about salaries even looked at the BBC's fiscal report?
With a Revenue of ~£5 billion. Programs are ~£700m, executive/board pay is ~£4.5m, salaries are £1.45b overall ( the rest is i guess licensing/rent/whatever).
They employ 21,583 as of last year of which 20 are the board and committee so 21563 employees at a median salary of £42k (average is ~£38k), so assuming you'd want to reduce the median to the national median (which is just cruel considering the industry pay levels), that would potentially make up a similar number to the new policy.
The fact is that executive pay is actually not out of control and wouldn't do anything to their shortfall in the future, the pay for the whole staff could probably use a little cut, but i doubt it's going to help much when the fact is that those over 70's are going to become a rather chunky part of the population while everyone else reduces their usage of the service altogether.