Heat the oil in a saucepan. Meduim heat. Add the chips. Cook until crispy and brown. Drain the excess oil.
In a saucepan, heat the pan and add the bacon. Fry the bacon until crispy. Add the onion and garlic. Fry for 5 minutes. Place the bacon and onion in a bowl.
Using the same saucepan, heat the butter, add the flour. Make a paste. Add the milk gradually, whisking constantly until a thick sauce. Add the cheeses.
Add the bacon mix to the sauce. Pour over the chips and enjoy.