OK, I thought my post may upset a few, but I have really struggled with a few small turbo diesels towing, much less than the maximum rated load. The Navara I was using was a 2005 model 2wd, therefore no option of selecting low range. OP never suggested he was using a 4wd.
After towing tradies trailers, boats, car floats, loaded box trailers and all sorts of construction equipment, for more than 20 years, I think I know how to do a hill start, maybe there is a technique that I have overlooked over the years? I'm always open to learning new tricks.
Sorry OP to stray off topic, although I did answer the question.
I will crawl back under my rock now.
Steve