What recipe are you using it in? I would not use ketchup, except perhaps as a last resort. I'd finely chop a fresh tomato or two, would add a tablespoon per tomato of cider vinegar (or red or white wine vinegar in the alternative), a tablespoon of brown sugar, some Worcestershire sauce, some crushed mustard seeds (or 1/2 teaspoon coarse brown mustard), a pinch of ground coriander and some red pepper flakes, if you want some heat. I'd stir that up. cook it gently for about five minutes, then let it sit for an hour. If it were not possible to do this, and the purpose of the chutney was simple to add the chutney flavor to the recipe, I'd use a good ketchup, ideally with an equal amount of diced fresh or canned tomatoes, and add the spices noted above, and vinegar equal to a third of the total volume of the ketchup and/or tomatoes. Good luck! ;o)