Do you really believe that an alternator failure could have led to a loss of life?
If an engine timing belt or timing chain tensioner failed as you were driving along the effect on the power steering would be exactly the same, it's an unforeseeable event.
Components fail, especially on older vehicles.
If heat blew the alternator diodes, maybe there was no UK recall because Britain is not normally a hot country, and the recent hot weather caused the alternator failure?
It's fortunate that no one was hurt when you lost all power on the motorway, but I doubt if the DVLA would be interested if you as the driver coped with this random incident without injury to yourselves or to any other road user.