UK Stocks-Factors to watch on April 26

April 26 (Reuters) - Britain's FTSE 100 index is seen opening down 2 points on Wednesday, according to financial bookmakers. * BHP: BHP Billiton, on Wednesday trimmed its full-year production guidance for iron ore, coking coal and copper due to bad weather at mines in Australia and industrial action in Chile over the last quarter. * ROYAL BANK: British Bank Royal Bank of Scotland toxic debt settlement was delayed because of changes at the Department of Justice since the electi