6 weeks and five days door to door here. Went with Anglo who use Maersk. That actual sailing departed 13 April and arrived 22 May, with transport and customs accounting for the rest. You can check Maersk's timetable yourself. Mine went on Stralsund changing to Jubail at Singapore. They have route numbers just like busses. I had sole use of 40 ft container too. There are things you can do to help. Get in touch with your agent in NZ at least two weeks before your ship is due in and complete ALL the customs forms. If shipping a car and its on last, be available to go to customs on the container due date to sign the GST waiver form. Until the car is released, the rest of the stuff cant come off if it was loaded last. At the UK end, time your packing to coincide with a scheduled departure, allowing a bit of time for the paperwork and the road journey to port. I think you do pay slightly more for the faster sailings, but not by much. Make sure you know your packing list inside out, so you know exactly what packages MPI will show interest in, this will help filling in the forms in NZ.