Firstly, prepare your orange peel, a little less than specified is not going to make that much difference. Dice the peel into pieces about ½ cm square. The peel won't reduce in size during cooking, so you need it to be quite small.
Put everything into a saucepan and bring to the boil
The orange peel and onion need to be cooked through and tender. Simmer, with the lid on, for about 45 minutes.
Click here for a timer
The chutney needs to be the right consistency. It will thicken as it cools. At this simmering stage, it needs to be like chunky jam.
Prepare your jar(s)
While the chutney is simmering, preparing your jar(s).
Sterilise them by placing in a large mixing bowl and pouring boiling water over them. Or wash thoroughly and warm in a low oven. Make sure then are are dry before you use them.
Jar up the chutney
Once both the chutney and jars are ready, place on a heatproof surface, like a chopping board.
Carefully spoon in the hot chutney, a jam funnel is helpful with this. Place a square of greaseproof paper on top and carefully screw on the lid - the jar will be very hot, use a tea-towel to protect your hands.
Once cool, wipe the jars to remove any spills and label, including the date
Leave your chutney for a month before using. It's perfectly edible before that, but will be very vinegary and unpleasant.
Notes
I used white vinegar as I get it in bulk and use it for everything from cleaning to cooking.
You can swap all or some of the orange peel for any other citrus peel to get a different flavour, lemon or lime for instance.
The sultanas can be swapped for currants, raisins or any other dried fruit.
No coriander seeds? No matter, you won't notice just leaving them out.
I increased the cayenne to a full teaspoon as I wanted a little warm hum.
If you don't have brown sugar, you could use ordinary white sugar, and a couple of tablespoons of black treacle. Don't have that either? I haven't tried it, but it would probably be just fine with just ordinary sugar.