I have a relative aged 70+ who works for M&S. The store she works in is open. My understanding is that people aged 70+ are strongly advised to stay at home, but as yet the government has stopped short of instructing them to do this.
She feels she has no choice but to go in for her shifts as normal, as the only alternative would be to resign. She has a very strong work ethic, and would never dream of pulling a sickie.
I feel large companies who employ people over 70 have a moral duty to tell them they are allowed to go home, and that they should be paid.