19d "Arse gives rise to waffle and viscous mixture (6)
I've got - - - B - G and presume its GASBAG but can't parse it.
Also, if that's the case, not sure what 21a would be i.e. "Bureaucrats: 'terrible leader, Miliband ultimately on the inside' " (5)
where I've got - - M - N
Any help greatly appreciated