By Aashika Jain (Reuters) – British IT services provider Computacenter Plc reported a rise in full-year group revenue that exceeded analysts’ estimates, boosted by a strong demand for its maintenance services in the UK. Shares in Computacenter, which sells PCs apart from providing services including software upgrades, rose as much as 4.6 percent on Thursday, making the stock one of the top gainers on the FTSE-250 index. Revenue grew 6 percent in 2013, said Computacenter, whose clients include Lloyds Banking Group, Serco Group, British Telecom, Deutsche Bank, WM Morrison and EDF. …