alex Salmond and the SNP were dealt a blow by a new survey last night which found that only one in 20 companies north of the Border believe that independence would have a positive effect on their business.  More than two thirds, 67 per cent, of the 109 companies that responded to the survey said it would not have a positive effect, 5 per cent said it would have a positive effect, 17 per cent said they did not know what effect independence would have, and the rest said it would have no effect.  The survey comes only a few weeks after Citigroup, one of the world's biggest financial institutions, warned its clients to exercise "extreme caution" and take a "precautionary approach" to investing in the renewables sector north of the B