Its a nice house and there is nothing really wrong with it but you need to invite people a bit more to come a have a look at it.
Get some new photos and ask the estate agent to put measurements on the floorplan. People need help imagining themselves living in your house. Not everyone has the imagination to see past your stuff.
My first thought was why is there no picture of the dining room? It makes me think there might be something wrong with that room. Some people might also not even look at the floorplan first and assume your house is smaller then it is.
You seem to have some potted plants in the back garden, I would brighten them up and bring them up front to make it look more inviting.
The living room looks smaler then it is because of the clutter and everything is against the wall. Center the rug, place a coffee table on it and remove the clutter from the fireplace and bookshelf. If you or a relative have a nice armchair, place it close to the bookshelf and lamp. Also the flower painting looks to high up, I would hang it at the same hight as the mirror to give the impression of a higher ceiling. You might also try hanging the mirror portrait instead of landscape, as this too can sometimes create the illusion of a higher ceiling. This room also has the problem that with the sofa facing the fireplace, this only highlights it as a problem. I know its painted the same as the walls but it kind of looks like two sheets of cardboard. Maybe place something in front of it so that it becomes more of a frame and a quirky feature instead of a empty hole and flaw that is grabbing all the attention of the room. All this will make it look more like a comfy living room instead of like a playroom for the children.
The kitchen needs decluttering and the pictures needs to be taken from further back or different angels. It was only when I looked more carefully at the floorplan that I realised there was space for another door. I might also move the bin against the wall you don't see or get one that fits in the under the counter cupboards.
Remove all the kids stuff from the garden and place some chairs out.
Declutter your bedroom, especially under the bed and remove the little bookcase. Cover the bed with some white or cream covers because some people really don't like purple and it will mach more with your fabric wardrobes. Remove the chair.
If you can move one of your child's wardrobes to the wall we can't see or to the hallway. It might look okay opposite the stairs (if it fits). This will make the room look a little bigger.
The pylons would put me off, but there is nothing you can do about that.