Kanga offroad camper trailers - advice

Mal.... We purchased one of their BIG RED DELUXE off road trailers in 98 and since then have used it on various local off road camping jaunts over long weekends while we were members of a local 4wd club as well as travelling to Lawn Hill in 2000. We requested an extra water tank to be fitted ( giving us 120 litres ) as well as some of their standard options. To date I have had to modify the water lines connecting these tanks as the first time that we used it, when it was parked on an incline the water in the rear tank siphoned into the front tank and overflowed out the breather on top of the tank eventually losing most of the water in the rear tank. Now I have a tap fitted in the filler tube between these two tanks, a tap on the suction line between the tanks and a tap isolating the plunger pump at the sink. As well on the first fill nearly every water fitting leaked which was annoying.
The up side is that it comfortably carries all of our personal gear and food for a family of four ( could sleep up to six people in the enclosed tent area if necessary ) and tows well behind our Patrol Wagon at highway speed.
If I was in the market for another camp trailer I would have no hesitation in considering purchasing another KANGA as I feel that they are only limited in their capability by the tow vehicle.