On the Chinook now versus MPA in the future (force balance), how would we have managed in WW2 is we had said we won't need all those Lancasters in the 50s but we will need lots of Lancastrians. We should balance our forces.
The Chinook is needed NOW. Year after next it should not be needed in as large a number so the older ones should be scrapped. The money saved stopping running redundant helicopters can then be diverted to MPA or whatever.
That is reality.