GUARDIAN Royal Exchange has sold its remaining stake in the Courtyard Shopping Centre in Letterkenny, Co Donegal, for slightly more than £3 million. The company's holding has been acquired by the joint developers, auctioneers Mr Paul and Mr Joe Reynolds, and a Buncrana builder Mr Michael Hegarty. They are now planning to sell on their interests in the centre which is located in a tax designated area. The owners say that the present rent roll of £470,000 per annum could reach £700,000 if tenants were found for 20 per cent of the space still available.