No drivers will still operate on their allotted lines, any attempt to
change this arrangement and introduce an element of flexibility would
have to be negotiated with the unions, drivers are also supposed to
drive over a route at least every 6 months to retain their route
knowledge, although I'd happily never see Chesham again!

The reason that all the carriages are decorated with Met diagrams is
that the Met will be the first line to get these new trains.

True, but if the stock is transferable can the drivers also be trained for
redeployment and specials where necessary?