UPDATE 1-UK Stocks-Factors to watch on April 20

(Adds company news items, futures) April 20 (Reuters) - Britain's FTSE 100 index is seen opening 21 points higher at 7,350 on Friday, according to financial bookmakers, with futures up 0.32 pct ahead of the cash market open. * BARCLAYS: British regulators have concluded efforts of Barclays chief executive Jes Staley to unmask a whistleblower at the bank represented a breach of individual conduct and proposed he pay an undisclosed fine, the bank said on Friday. * ROYAL MAIL: