These guys don't guarantee to take you & vehicle home though "National Recovery An extension upon our Local Recovery. If a recovery operator is unable to mobilise your vehicle at the roadside or home address, we shall decide and recover the vehicle to either a suitable garage, your home address or your destination. One of the above options will be arranged by our experienced team with all factors taken into consideration, such as, but not exhaustive to; the time of day, type of repair required, number of passengers, your location."
It comes down to driver hours usually, hence the ‘relay’ bit of AA. RAC have never done that to me and always had a single recovery all the way back.