Cut the fruits into eighths and then put in a jam pan with the water. Bring to the boil and then allow to simmer for at least an hour, better still two hours to extract all the juice and taste.
Allow to cool and then strain through a jelly cloth. Allow it to do this slowly to allow it to be as clear as possible. Personally I leave it overnight.
Measure the liquid and allow 450g sugar to each 600ml of juice. Return to the jam pan and bring to the boil and allow to boil rapidly until the setting point is reached. This is when the temperature reaches 105 degrees C, if using a jam thermometer. Or else test at regular intervals by placing a small amount on a saucer and then place it in the fridge for 2 minutes. If it wrinkles when you push it with your finger then the setting point has been reached.
Remove from the heat and allow to cool for about 5 minutes. Using a perforated spoon skim off the scum that has formed on top. This can be used to flavour cakes or puddings.
Using a jug pour the marmalade into hot sterilised jars. Add a pinch each of the silver and gold flakes. Stir frequently as it cools until the flakes stop rising to the top. Seal the jars and label.
Gold and silver flakes are readily available via specialty shops or the internet as glitter and leaf. It is admittedly rather expensive, but it does go a very long way and looks very decadent.