To still be Prime Minister after the election Helen Clark needs to achieve a few things. She needs to keep National from winning an absolute majority. She needs Labour to get up to 37/38% support. She needs NZ First and the Greens to get over 5% support. And she needs these two parties, plus the Maori Party to support her after the election.
Now the PM also knows that NZ First is a one person party. Without Winston they are nothing. So she doesn't want Winston to be up on charges and she doesn't want Winston's campaign to not be functioning.
Winston's office is key to a successful campaign. If Winston had been fired and dismissed as a Minister for good he would have lost his office, and pretty much all hiss staff. These staff members are his eyes and ears and the people that do all Winston's leg work.
David Farrar is on to this. Read this post. Winston has been able to retain his office and most of the baubles. It is really only his image and ego that have taken a bit of a hit.
