As you say there is a radiator on the left then I would put the sofa against that wall and the tv opposite. You don't really want it (the sofa) in front of your french doors. As your wc is opposite the designated area for dining the door swing takes at least 800mm off the available space. If you changed the wc door to a sliding one it would help with space. I wouldn't want my dining table so close to the wc. I would consider combining the lounge/dining with your furniture as the space for the table is very tight. Try it though. It might work. Make scale cutouts if you don't use sketchup and play with the layout. I usually find the previous house's furniture seldom works in the new house.
Q
