Sept 22 (Reuters) - Goldman Sachs said on Tuesday its UK headquarters will remain open to staff who need to remain in the office following calls from the British government to work from home, an internal memo seen by Reuters showed. “You are reminded that the wearing of masks is required at all times in the office, except at your desk,” chief executive officer of Goldman Sachs International Richard Gnodde wrote in the memo. (Reporting by Ann Maria Shibu in Bengaluru and Sinead Cruise in London Editing by Chris Reese)