Here are my thoughts (lovely house though):
Take out green rug from sitting room
Remove both green armchairs from sitting room
Clear a lot of the shelves in the sitting room. Put books stacked horizontally in the centre to make it look less cluttered. Get rid of the boxes.
Put a mirror over the fire if you have one
Completely clear the kitchen (and repaint neutrally if you can)
Agree with above posters regarding the spare room and baby's room.
The extension looks unused (although it may just be the photos), turn it into something? Put the green armchairs in there with a lamp and some books and it becomes a reading room or a study etc, it gives people something to work with!
I agree re the fridge too.
Might be worth re pointing that wall of the garage.
I also agree that while the house is lovely, there is quite a bit to do (and it's the most expensive bits that can't really be DIY'd) so maybe double check pricing.
Good luck!