Really? A litre of milk in the evening? That, my friend, may be one of the biggest things holding you back. Dairy is famous for slowing or stopping weight loss. Think about it - milk was designed for GROWTH of infants of all mammalian species.
Could you maybe try having a small portion of some fatty meat for it's high satiation factor? Or fruit? Or an ounce or two of a deeply dark (meaning low sugar) chocolate? Or a measured out ounce or two of unsalted nuts. If you're not eating low carb, then maybe a bowl of cereal with just 125-175 mls milk (1/2-3/4 cup). And calorie free beverage ad lib.
Check out some on the online resources about the Primal Diet, Intermittent Fasting, Bulletproof coffee. There are lots of things you can try.