OP, I made a few minor decoration / dressing for sale suggestions the other day. I just thought I should be clear that those things are most valuable for the sake of the photos. You need attractive, good quality photos to catch people's eye, so attract viewings.
Once people are in, a lot of people can see past your decoration and furnshing and get their own sense of the size of the rooms etc.
For the photos, a painted wall or two (the one to the left of the wood burner most obviously) would help. Plus some of the lighting, curtains and tidying tips others have offered.
Then get the EA to take better quality ones from better angles, showing more features (paddock, garage etc).
I'd be selling the 'potential annexe' rooms as 'home office / playroom with potential for conversion to self-contained annexe'.