Ida thought a second chamber would be relatively easy to establish - same powers as current HoL, 300 members selected by PR of votes cast in Scotland, Wales, NI & English regions at GEs, simple to put in a manifesto.
Main drawback would be the people chosen would be "party hacks" - same difference really.
As I say easy to implement and you could have some sorta review after 10 years to see if it was working.