Pierce the oranges with a fork. Remove the stem and noble root. 

Now place them into a pan and cover with the designated water.

Bring to a simmer and cook the oranges for an hour slowly. Allow the ranges to cool in the water. 

Now the messy part!

Remove the oranges onto a cooling rack with a tray (collect the juice). Cut each orange in half and scrape out the insides: place these into a muslin cloth. Now cut the remaining skin into nice julienne – your choice of thick or thin comes to bear. Once this is is all wrapped up, seal the muslin bag with string, add the sugar to the orange(y) water, then add the muslin bag and lemon juice. Bring this to the boil and simmer until the sugar dissolves.

Now add the beautifully chopped orange zest and cook very slowly for around an hour and a half.

Test the marmalade on the chilled plates. If it sets, you are good to go. 

Allow it to cool. Store in sterilised jars and away you go Paddington.