Oh good, not being able to see the trailer is a reason for not being able to reverse it. I've tried to reverse mine and have ended up almost jack knifed. Can't see the trailer at all until it's gone too far.
I know the theory and can reverse a flatbed trolley moderately successfully but trailer is likely to end up not good.
Pragmatic, no point in faffing about cocking up a reverse when it'd be far quicker to unhitch and push.
I pity the arctic drivers that deliver to our local Co-op. Not only is there only just enough space to swing the cab around, they have to get close, less and 12", to a wall higher than ten trailer as the loading bay is to the side. But the ground isn't flat, where the donkey is maneuvering has a steady slope up, a few feet adjacent to the wall is flat but further away also slopes up. Meaning the rear top offside corner of the trailer is somewhat closer to the wall than the trailers rear wheels, until the trailer is almost parallel to the wall.