Simon Cowell has netted a £50 million-a-year pay day. The 65-year-old music mogul’s windfall is said to be due to the worldwide success of his television empire, with Simon earning nearly £1 million a week, according to accounts filed by Syco Holdings. It’s the firm he uses to manage his hit ‘Britain’s Got Talent’ show, and figures first obtained by the Daily Mirror, which were submitted to Companies House, showed a £21.9 million pre-tax profit on a £32.6 million turnover in the business in the year leading up to March. Half the cash was said to have come from the US, while there was £7.1 mill…