The best way to make a meatloaf is in a large food processor, if you've got one.
Begin by chopping the onions, garlic, parsley and thyme all together until the onion is very finely chopped, then add the meats and break in the egg. Place the bread in a little bowl, spoon the milk over, then mix it with your hands or a fork until the bread has broken down to fine crumbs. Add these to the processor along with the mustard powder, Worcestershire sauce, wine and a really good seasoning of salt and pepper. Now, switching on and off, or using the pulse button, mix the whole lot together until thoroughly blended. If you don't have a food processor, grate or mince the onion, chop the garlic finely then mix everything thoroughly in a large bowl.
When the mixture is ready, pack it into the loaf tin and smooth the top with the back of a spoon, then snip the rinds off the bacon and lay the slices all along the top of the meat, slightly overlapping, and press them down firmly. Now place a piece of foil over the top and twist or pleat the corners. Stand the tin in a shallow baking tin, pour about 1½ inches (4 cm) boiling water into the roasting tin straight from the kettle and place the whole thing on the middle shelf of the oven. Let it cook slowly for 2 hours; you may need to top up the water halfway through cooking.
To make the relish, first you need to skin the tomatoes, so pour boiling water over them and leave for exactly 1 minute before draining them and slipping off the skins (protect your hands with a cloth if they are too hot). Put the onion, chilli, garlic and tomatoes in a food processor and blend until finely chopped, then place the mixture in a small saucepan and add the sugar and vinegar. Place the pan over a gentle heat and simmer very gently, without a lid, for 2 hours, by which time the mixture will have reduced to a thick sauce. Towards the end of the cooking time, stir frequently so the sauce doesn't stick tot he bottom of the pan. Then taste to check the seasoning. When the meatloaf has had its 2 hours' cooking time, remove the foil and insert a skewer into the meatloaf; press it down to make sure that the juices are running clear.
Now, if the meatloaf is cooked, remove it from the oven then let it cool for about 30 minutes and after that, if you're serving it cold, replace the foil and place something heavy on top to weight it down. Leave it weighted like this until it's completely cold. This makes the meatloaf easier to slice. If you're serving the meatloaf hot, just allow it to rest for 30 minutes in the tin, covered with foil, then turn it out on to a board and serve cut in slices. The relish can be served hot or cold.