Air New Zealand - Excess Baggage

Hi there,
We're flying NZ1 on Sunday and we're going to have a little bit of excess luggage. We'll have 2 x cases each and 1 piece of hand luggage each. The cases are well withing the 64kg limit, but we'll also have a pet trolly with us as well.
It's this:

but it does fold down flat.
I called Air NZ and they charge £152 per extra piece of luggage [:0] so I suggested the possiblity of strapping the trolley to one of my cases, and her response was "no worries".
Now, my only concern is that they don't agree with this at checkin or they start to get the measuring tape out, because we're just over the 62" that you're allowed.
Does anyone have any experience of excess baggage with Air NZ?
I thought they might be a bit more flexible since we're emigrating and flying business premier. [:I]
Milliemoo
We're flying NZ1 on Sunday and we're going to have a little bit of excess luggage. We'll have 2 x cases each and 1 piece of hand luggage each. The cases are well withing the 64kg limit, but we'll also have a pet trolly with us as well.
It's this:

but it does fold down flat.
I called Air NZ and they charge £152 per extra piece of luggage [:0] so I suggested the possiblity of strapping the trolley to one of my cases, and her response was "no worries".
Now, my only concern is that they don't agree with this at checkin or they start to get the measuring tape out, because we're just over the 62" that you're allowed.
Does anyone have any experience of excess baggage with Air NZ?
I thought they might be a bit more flexible since we're emigrating and flying business premier. [:I]
Milliemoo