CLOTHING retailer M&Co is moving into the renewable energy market after yesterday unveiling plans to erect GBP20 million-worth of wind turbines on farms in Scotland.  Mackays Stores Group, M&Co's Inchinnan-based parent company, will use the electricity generated by the turbines to power its network of 300 UK stores.  The company already buys renewable energy but now wants to generate its own power to insulate itself against rising electricity prices.  Mackays changed its shops' names to M&Co in 2006. The group was founded as a pawnbrokers in 1834 and switched into selling clothes in 1961 when brothers Len and Iain McGeoch took over full control of their family business.  Neil McGeoch, Iain's son and managing director of the new MEG Renewables subsidiary, hopes his background as a beef farmer in ayrshire will help him to win over landowners to host wind turbines.  The group wants to erect between one and three turbines o