Scrub the fruit and put in a preserving pan with 3 litres of water.

Bring it up to a gentle simmer and then cover the top tightly with foil.

Simmer for about 3 hours, resist the temptation to peak as you want to keep as much of the liquid as possible.

When the fruit is cool cut each orange in half and scoop out the flesh and pips and place in a new saucepan. Keep the peel separate. Do the same with the lemons but don't keep the peel.

Add half a litre of the poaching liquid to the flesh and pips, bring to the boil and simmer for ten minutes.
If using quince pulp boil it up with the flesh and pips as well.

Slice the peel (this will be easy as they are so soft) and put the peel back in the preserving pan.

Drain the flesh and pips over a bowl through a piece of muslin in a sieve. You are trying to get as much of the pectin rich liquid out of the pulp as possible, so may need to squeeze the muslin. Discard the pulp when finished.

Put all the liquid back in the preserving pan. (now is a good time to stop for a nights sleep if need be)

Put the sugar in a roasting dish (If using quince pulp use extra sugar in the ratio of 2 sugar: 1 quince by weight) and warm for about ten minutes in an oven at 170 degrees centigrade.

If using membrillo roughly chop it now and add to the pan.

Put the preserving pan on a gentle heat for a few minutesthen add the sugar, stirring until it is dissolved. Don't let it boil until all the sugar has dissolved.

Turn up the heat and let the marmalade gently boil for 3 -4 hours until it has reached setting point.

Allow to cool for half an hour, so the peel doesn't float to the top of the jars.

Pot in sterilised jars