COMPUTER book shop Unihall is expanding its operations into a huge retail complex in Causeway Bay. The company, which specialises in discount software, already has shops in Central, Admiralty and Tsim Sha Tsui. Mr Thomson Lee, managing director of Leed and Wood, the firm which owns Unihall, said the move would go ahead late next months. He said: ''We are moving to a location where we do not have a shop at the moment. ''We think that the traffic there will benefit us as it is such a vibrant area. ''I am sure the shop will benefit from tourists and local people alike.'' Leed and Wood is renting 16,000 square feet of space on the 11th floor of the In Square retail building overlooking Victoria Park. Formerly known as Windsor House, the commercial complex was bought by Chinese Estate. It re-fitted the 15-floor tower so it could become devoted to retail. Leed and Wood is renting space at $50 per square foot per month, including management fees. Mr Lee planned to sub-let some of that space to other computer retail outfits.