Less than a month after buying 5.35 per cent of Datalex’s shares in an off market transaction, Irish businessman Tom Anderson has sold most of his stake.  Datalex shares have been suspended from trading since April when “significant accounting irregularities” were discovered at the firm. But that hasn’t stopped investors. Since late December, some 15 per cent of shares have changed hands.  In the most recent transaction, on January 17, Tom Anderson’s Cinema Holdings Limited sold 3.21 per cent of its Datalex stake. It had acquired the shares on December 20, only four weeks before. It’s left with a 2.14…