By James Davey and Elizabeth Piper LONDON (Reuters) -An inquiry into COVID-19 lockdown-breaking gatherings in Downing Street that might determine the future of British Prime Minister Boris Johnson could be further delayed after the police asked for the report to make only “minimal reference” to those events. Johnson, facing the gravest threat to his premiership over the alleged lockdown-busting parties at his residence and office at Number 10, has so far weathered growing calls to resign over the events, asking for lawmakers to wait for the report. Led by senior civil servant Sue Gray, it is l…