Radio 4's 'Feedback' [1] bills itself as "The programme that holds the BBC to account on behalf of the radio audience" and frequently interviews BBC employees.

Obviously there are fraught incentives from them paying for their own criticism. Not sure cancelling the program would improve the situation though.

[1] https://www.bbc.co.uk/programmes/b006slnx/episodes/downloads

Not to hand but I'm just having a search for it.

I'm pretty sure it was PM with Eddy Mare on Radio Four and from memory would have been back in 2017.