England - on holiday in NZ. Flight cancelled. Where do we stand?

Currently on holiday in NZ (North Island) until 19/2. We then planned to take a flight to a friend's wedding in AUS on that date, stay for a week and then fly home to England on 24/2.

We have received an email today while we are in NZ telling us that our connecting flight has been cancelled, and a new one has been organised for 21/2.

We are touring in a camper van in NZ and we won't have any accomodation beyond our original flight date. We also will lose out on our original accomodation we booked in AUS and lose the cost of that . Of course we are missing some of our dream holiday too!

Cheers Travel who we booked the original flight through are asking us to accept the new flight that has been offered (We are reluctant as the

We have travel insurance through Admiral and their opening times are polar to our awake times (they close at 5pm) although we are going to call later when the times overlap.

Any ideas on the best way to sort this out? Ideally we want to fly the same day as we don't want to lose any accomodation or pay for anything new.

Hoping to hear from someone "in the know" in travel insurance or travel or someone who has experienced similar.

Many thanks