Place eggs in a saucepan, cover with cold water.
Bring water to a boil and immediately cover and remove from heat.
Let eggs stand in hot water for 10 to 12 minutes, and allow to cool in pot.
Place bacon in large pan and fry. Finely slice and set aside.
Mix together mayonnaise, bacon, cheddar cheese and mustard.
Peel the hard boiled eggs, cut lengthways and remove yolks.
Mash yolks into the mayonnaise mixture.
Place the mayonnaise mixture into a piping bag with a large nozzle, and pipe into the centre of the egg.