Cognac, mustard yellow and moss green
In addition to grey, cognac is the most popular colour in the selection of sitting rooms in this style. Cognac is a warm, cosy shade that works surprisingly well with nice contrast colours such as mustard yellow. But moss green also looks nice in combination with cognac. A big ottoman in the same cognac leather, a dark wooden TV cabinet and you're all set for those long cold winter nights.
Add another open cabinet in matte metal or an old cabinet, aged or not, and put a vintage metal lamp on top of it. After all, your furniture and accessories can have a past. Recycling is trendy for a reason!