UPDATE 3-UK Stocks-Factors to watch on Jan 31

* SSE: Britain’s second-biggest energy supplier SSE continued losing customers in the third quarter of its financial year, while still and wet weather meant output from its renewable energy plants fell 20 percent year on year, it said on Tuesday. * BRITVIC: British soft drinks firm Britvic said first-quarter revenue rose 4.3 percent on strong sales of its drinks in Britain and international markets.