"MPs will not reform public sector pensions"
Except when they changed how they increased from RPI to CPI (2010). And when they increased member contributions by 3.2% of pay (from 2012). And when they changed them from final salary to CARE and increased pension age to SPA (2015).
But as you note, MPs will not reform public sector pensions because they enjoy generous defined benefit pensions themselves. They know the media and public never focus on this. Yet the total cost of public sector pension commitments is £2.3 trillion.