Pre-heat the oven to 180C/360F fan-forced. Grease and line one big rectangular tin or two smaller ones.
In a large bowl mix together the muesli, flour and sultanas.
Melt the butter or margarine, honey and brown sugar in the microwave for 1 minute and add to dry ingredients. Stir in the egg and milk until well combined.
Press into the tin and bake for 15 minutes at 180C/360F fan-forced. I used two shallow tins for mine to make them the right height for bars.
Cut into bars when cooled.