It's a decent part of Sheffield if my memory serves me correctly from an Aunt who used to live not far away from you.
It doesn't appeal from the outside - can you do anything to improve the kerb appeal at all? It also seems to be overlooked at the back which would really put me off.
Inside:
Picture 2: It looks like a lovely room but the chairs close to the camera look like they are squashed together by the fireplace (?)- maybe remove one while a new photo is taken?
Picture 3 & 5: I'd put a plant or bunch of flowers in the middle of the table to make the house opposite less obvious.
Picture 6: Add a bowl of fruit or the infamous stunt pineapple. I love the colour - and the pineapple would match! The room could do with some brightening up - the work surface is too clear. Can the picture be taken from a different angle? What is on top of the oven?
Picture 8: Are there stairs in the corner of the room? Have the picture taken without them. There don't appear to be any banisters? It detracts from a picture of a nice room.
Picture 9: The step up bit puts me off - not safe for children and not practical for older adults. I'd step back and fall off it! I'd also wonder if there was enough head room.
Picture 10: What is up those little stairs? It's a quirky room and I like it.
Picture 11; Can you do something to the window like blinds to take away the view of the house opposite. It's a lovely room but seems like you have no privacy.
Picture 14: How do your neighbours feel about the telescope?! 
Picture 15: Declutter!
Picture 16: Isn't there a door on the room?
Picture 18: people will look at that and see a room that they need to retile. I'd happily keep the orange but would see the picture tiles and think I need to do the whole wall - or are they tile stickers that you can remove?
Picture 19: Put a blind on the window - people can see you in the shower when the lights are on.
Picture 20,21,22: Ditto the picture tiles.
Picture 26: you've got no privacy in your garden which would totally put me off. Up until seeing that picture it would have been a house I'd choose to view because i love the colours you have used