MG GS Owner's Handbook Manual page 277

EMERGENCY INFORMATION
Transporter or Trailer with Rope
If your car is to be transported on the back of a trailer or
transporter, it must be secured as illustrated:
Position the car on the trailer, apply the hand brake and
place the gear shift lever in neutral. Fit wheel chocks (1) as
shown, then position the anti slip rubber blocks (2) around
the circumference of the tyre.
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Fit the lashing straps (3) around the wheels and secure to
the trailer. Tighten the straps until the car is securely held.