Thad Jarvis It was always transferable but only between participating airlines operating the same type. This is where the Monarch cadets recent got lucky with easyJet whereas Flybe Q400 MPL would not be transferable to A320.
This is totally incorrect I'm afraid. All that said Q400 MPL holder would need is their licence derestricted from Flybe after final line check (paperwork exercise) and then an A320 type rating.