LONDON (Reuters) – British business leaders have turned more pessimistic about the outlook for the country’s economy and they are holding back on investment decisions, according to a survey published on Wednesday. The Institute of Directors’ (IoD) confidence index – which maps the gap between business leaders who are optimistic about the economy and those who are pessimistic – fell to -28 in December from -21 in November, having gradually risen since June. Expectations for business investment, costs and wages, and headcount were all little changed. Despite the caution, company leaders were mor…