On 14 Apr 2018 13:15:42 GMT
David wrote:

Two basic requirements:

(1) Shows the location of the corners when reversing.

(2) Remains fixed to the trailer and undamaged when towing at the
legal maximum of 60 mph on dual carriageway.

The suggestion was that the poles needn't remain in place - they could
just be attached before reversing, then removed and stowed away.