Nailak, just a few ideas. I am sure the property could look a whole lot better with a few cosmetic changes and, very important, new photos. It is basically a good family house and I am certain there would be people who would love to live there.
Remove a sofa from the sitting room (will it go into the shed or could it be shipped off to someone else's spare room perhaps?). Use some light coloured throws and cushions to cover some of the brown leather. Take everything off every surface in the kitchen (it can be put back after the pic is taken if there is really no space for it - hide it under beds, anywhere, while people are viewing). Put a one-colour throw (black? or even better, white) on top of the black and white bed cover).
Replace the shower curtain with a non-patterened plain colour. Scrub all the grout using an old toothbrush and mould stuff (think there are several makes), remove towel for photo. If possible, paint the interior of the window frame white.
Show more of the garden if this is possible, other than just the shed.
I don't know the area but it sounds good value and is near a Tube station. Someone coming in will want to put their own "stamp" on it anyway. Good luck to the vendor!!