I think you could make it look better for the pics, though the price/stamp duty may be the real issues.
I would put your kettle on the kitchen worktop and fruit bowl etc just so the kitchen looks more lived in, rather than a show home.
I do agree re the yellow walls (esp against black furniture), might be worth painting them in a more neutral colour.
I would also make it more cosy, add a rug/throw/cushions to your living room, and perhaps move the dining table so its more central to the room (if you can borrow a bigger table then even better).
I also agree re moving the cars and I would add a couple of large pots with winter pansies to the back garden for some greenery and colour.
Basically it could all do with some colour and life!
Also what is the square of sand by the patio? That looks a bit funny.