Sir Rod Stewart said he wanted to “prove I’m not all mouth and trousers” as he visited his local NHS hospital where he paid for a day of scans for patients to help cut waiting lists.Arriving in a white Rolls-Royce on a drizzly February day, the 78-year-old star said “hi everyone” as he climbed from the car outside Princess Alexandra Hospital in Harlow, Essex.The singer-songwriter last month called a live phone-in segment on Sky News and offered to pay for people to have hospital scans, having just returned from one himself.