I Seriously doubt anything will be done about the existing fleet, the number of cars impacted would be huge...and I seriously doubt the govt will stump up the 100s of millions/billions needed to actually make a real difference, + there is the issue of actual availability of significant numbers of EVs
JAG's Presence or Absence is pretty immaterial given that her Assoc. transport role went to James Shaw in her absence.
We'll find out in due course. If they are serious about doing something to address climate change then fiddling around the edges isn't an option.
As for JAG....I can see the announcement being delayed until her return and then Twyford and she can nail down the final details.
James Shaw was there in a care-taker capacity. I very much doubt he was driving. Too much else to do.