Travel software firm Datalex has experienced heavy volumes of off-market trading in the last two weeks with over 15 per cent of its shares changing hands.  Shares in Datalex were suspended last April after “significant accounting irregularities” were discovered at the firm, but a series of strategic moves by the business since then have again attracted new investor interest.   Highclere International Investors sold 5.13 per cent of Datalex on December 20 to an undisclosed party while Chicago-based Kabouter Management is thought to have sold out all of its position of about 10 per cent of the business recently. There may have…