and this is how i operate it
in the back of the road trailer i carry 4 x 25 ltrs plastic containers, 1 in the trolley and more in the van if needed, i use di at the moment but will be changing to ro when i move into new house with garage, the trailer is easy to reverse with practice but it's also light which means you can unhitch and move if need be in seconds, you will notice on the side of my cart it also has a small pointer (as i still do bottom windows trad methods), also the pole is attached to side of cart and bucket on top, inside the cart 3 compartments, (1) power pack kept dry, (2) room for spare hose if needed, (3) for 1 water butt. using this method i can park up the van in a road, push along cart and every so often walk back to my van, drive to the house that i'm working on to change water butt when needed. by doing this it saves me loading and unloading if you have a few houses in 1 road to do. you will also notice that the end of the trolley is left open i.e. not boxed in, the reason for this is to keep an eye on the water level and you don't have to lift the water butt to high (saves on back trouble) the other water butts on the trailer will slide off when needed from the tailgate (once again minimal lifting required) when it's time to load, the cart wheels up tailgate, unclip ladder and pole put into back of van and off we go. hope all this helps