There's also a difference in law about 'recovery' and 'transport'. For instance, a two wheel dolly or spec lift is legal to use for recovery of a broken down vehicle but not if you are simply transporting it to somewhere else, as the law says that any trailer weighing over 750 kgs must have all road wheels braked. As two wheels are on the road it is considered to be a trailer but the wheels on the road are not connected to the towing vehicles braking system, so it is legal for recovery but not transport. Recovery is defined as moving a non-functioning vehicle to a place of repair or disposal. I think the same general rule applies to using a rope or pole. If you are dragging a dead car off the motorway or out of a ditch, you can use a rope, if you are towing it simply to move it from one place to another, you should be using a pole.