Home-made tomato ketchup is really something else. My late grandfather, Harold Margetts, threw the household into confusion when, once or twice a year, he decided to make this excellent sauce. But it was worth it because it really cheers up a slice of cold meat when you cannot be bothered to cook or, indeed, even a cheese sandwich, and it’s brilliant with a slice of crisply cooked belly of pork. It leaves the stuff that you buy in supermarkets right in the second division a