LONDON — The chief data officer of Britain’s Conservative Party has taken a leave of absence, British media reported Sunday, following growing allegations that the governing party’s members used inside information to bet on the date of Britain’s July 4 national election before it was announced. The Sunday Times and others reported that Nick Mason is the fourth Conservative official to be investigated by the U.K.’s Gambling Commission for allegedly betting on the timing of the election. [time-brightcove not-tgx=”true”] The Times alleged that dozens of bets had been placed with potential winnings worth thousands of pounds. The reports came after revelations in recent days that two Conservative election candidates, Laura Saunders and Craig Williams, are under investigation by the gambling watchdog.