Thanks Stu for this post as it has been both an inspiration and source of information with everyone else also contributing. I bought a Red Witch in Jan 2017 and after sailing her for a few months, towed her home for a refurb. She started out as "Warlock" which is not a very feminine name for a boat, so we also renamed her "Summer Soul".
BEFORE

DURING

AFTER

Our boat is based at Nedlands Yacht Club and as with most people down there, we use the long rope method for launching as you will see from the rope hanging on the front of the trailer. Personally, I back the SUV until rear wheels touch water. Then rope is looped around tow ball, lift hitch and let out rope with one hand whilst guiding trailer down ramp with the other. You do have to be prepared to get into the water up to waist deep, however if you don't want that cold water shock, one of the members has fishing waders that he uses when launching. To get her out, I just hook up the other end of that long rope and pull her out. Obviously, all this is made easier by having the third wheel close to the tow hitch.
For those who have been wondering about the weight, officially Red Witches have a Displacement of 650kg (295kg of which is the keel).

Therefore, your trailer would need to be less than 100kg for it to be registered for <750kg and thus not require brakes. As you can see, my trailer is pretty basic and therefore I come in under this weight, but it should be something people consider when building/refurbishing a trailer. The more extension arms, thicker steel, fancier suspension etc the more likely you're going to go over this weight limit and require brakes.
Happy sailing and thanks again for providing such a great source of info and discussion.
Dave