I would highly recommend Anna Comber of The Travel Brokers. I have been using her for the last 5 years for both personal and school trips. Anna is great! Very efficient. Quick replying to emails. I am in Invercargill and even though she is North Island based, location hasn't proved to be an issue at all!
It is reassuring to know that Anna has a 24/7 emergency assist service available to directly contact her. I had to use this last year, as we were about to travel from Paris to Nice, but a last minute strike saw our train cancelled. Anna took the stress out of this situation by immediately rebooking the group on a train the following morning, as well as extending our accommodation in Paris by an extra night. She handled the insurance claim on this for me as well, which took a huge weight off my shoulders.