Well, after our old trailer died, we picked out a new one, and it's finally arrived! The neat thing about it is that the front, as well as the back, can be removed:
It also has tie-down points on the floor, so we can lay ratchet straps in to secure the logs without bending the side walls:
The result is that large loads of logs can be placed evenly across the axle, and everything works nicely!
However, we now have an additional solution for moving logs as well. Some locations are hard to access, and you have to push the trailer backwards up a track, then reverse the car up to it before loading and driving out. So given that we now have a Stein Arbor Trolley, I paid a local engineering firm to make me an extra part for it, so we can pull it with the 4x4:
It will come in very useful in future I think!