First things first: wash, core, peel and chop the tomatoes and apples, and whizz the onions in the processor until they are roughly chopped.
Pop the tomatoes, apples and onions into a big pan with the vinegar and simmer, lid off, stirring frequently so it doesn't catch on the bottom, until the tomatoes are completely soft. This takes a little over an hour, so put the kettle on! A potato masher gives a helping hand: once everything is soft, give it a good squish.
Add the sugar and stir until it has completely dissolved before you turn up the heat (undissolved sugar sinks to the bottom of the pan and can catch and burn, which would spoil the flavour of the whole batch).
Stir in the sultanas, spices, chilli, salt and bay leaf and simmer, lid off, for 1–1½ hours, stirring more often towards the end as it thickens. Start checking after 45 minutes.
In the last 20–30 minutes, have a taste and adjust the salt, pepper and chilli to suit you.
It's done when a spoon dragged across the bottom of the pan leaves a clear channel, or when a spoonful on a cold plate shows no watery ring.
Fish out the bay leaf, then pot the chutney into hot, sterilised 180 ml jars with vinegar-proof lids.