On the link from the Govt., i noted the following.....
"When reversing, it is advisable to have someone outside the vehicle giving directions"
I love it when a 70 something wife, bellows to her 70 something, hard of hearing husband, to stop, when the caravan is about 6 inches from a steel bollard.
He yells out.... "What? Speak up woman, for Christ sake" and then the corner of the van hits the bollard.
Then its on and for the next 20 minutes you've got the best entertainment you'll ever get.
OK, back to the rated shackles now......