Dingbatt:
Incidentally while researching this I have discovered how many kiwis are towing loads way beyond the capability of their vehicles.
I totally agree with this and have seen a number of cars towing horse floats when I know the car is not capable. For example a horse float will generally weigh around 800-1000kgs and your average horse would be 400-600kgs. So you might just get away with one horse on a braked float behind a car with a 1500kg capacity, but for me that's far too close to call particularly as people will often have gear and horse feed in the float as well which they won't have taken into account.
Some people seem to believe that its the size of the engine not the braking weight that is important. Additionally I've known of a family who towed with a BMW SUV (should be fine eh?) but it totally bent their chassis as it was not designed to have a tow bar attached to it for that weight and over the course of time it pulled out of shape.
And lastly I was towing my float one day following a Toyota Hilux. He had a lightweight trailer on the back which looked like it was from a DIY store. It was loaded with wood but only 4-5 high so nothing major. However, the length of the wood was far longer than the trailer although he did have an orange flag type thing tied to the back. As he came around the roundabout in front of me the trailer started to swing from side to side, I backed off very quickly and drove towards the kerb as I could see what was going to happen. He braked as he felt the trailer swinging badly (I'm guessing) and it jack knifed him across the road. Luckily for all of us there was nothing coming in the other direction and he wasn't going very fast just having left a roundabout. My point is that people don't think about the balance of a load on a trailer either which can be just as much of a problem.