David321:OP here, we are thinking of getting our own valuation, and asking the buyers to get one also from another company, (their bank will probably require one anyway). From there we would have two valuations to compare and could possibly meet in the middle if we both agreed that was fair. Or we could get them to get their valuation first as they will require one anyway, and ask them to show us, and see how that look to us.
On a side note, does anyone know the going rate for a valuation these days? (Christchurch area)
I wouldn't expect change from $1,000. I've used fordbaker valuation recently for valuations. Though in my case the homes.co.nz current value was pretty close in each instance.