While the rest of the country was distracted by events at Old Trafford, a corner of south-east London focused on the departure of another long-serving gaffer. Though Kenny Jackett’s departure as Millwall manager probably cause any palpitations on Wall Street, it was no less a surprise to supporters than Sir Alex Ferguson’s retirement was to Manchester United. A mere six years in charge doesn’t even come close to matching the reign of Govan’s most famous son. Such is the nature of English professional football, however, that by the time of his exit, Jackett had been in post longer than all but five of his peers. He’ll be almost as hard an act…