A BUILDING contractor, fighting to overturn his conviction for bribery, was forced to take his battle to the Governor, Chris Patten, after a legal bungle by the Court of Appeal. Liu Cheung-hon, 41, was convicted of bribery by Magistrate Peter White and fined $150,000 after the Eastern Court ruled he had paid an architect more than $60,000 as a ''sweetener''. Lawyers acting for Liu appealed on four grounds to Mr Justice Leonard. But the judge referred one point to the Court of Appeal. The Chief Justice Sir Ti Liang Yang ruled the magistrate had been right. But the court then dismissed Liu's appeal instead of referring the case back to Mr Justice Leonard. Liu's counsel, David Ma, wrote to Mr Patten, who referred the case back to Mr Justice Leonard, who will give his ruling today.