In terms of decor, it looks not just sterile but almost institutional. The living room photos are particularly bad, and especially the second picture (first of living room). Looks a bit like a short-term let, particularly with the carpet.
In addition to what everyone's saying, I'd ditch the coffee table (or at least put a few books on it to cover up its massive oakiness), put down a nice rug under the coffee table, and maybe add some art above the couch? Never close those French doors, either--picture four is far lovelier than picture two.
I'd try to warm up the kitchen as well. It's not just a horrible angle, but it also looks flat and dated.
Meanwhile, in the kids' bedrooms I'd tuck the rug underneath the bed to give the impression of more open floor-space/spaciousness.
In terms of price, looking at the house I'd be factoring in minimum of £10k for redecorating, as it currently stands. While MN is of course right that it's always about price, you have to imagine what people think they'd have to do to update it. Honestly, some better staging might knock my imaginary redecorating budget down to £2k or so, which would mean that in my head the house would be £8k cheaper than it currently looks (if that makes sense).