Several years ago, we wanted floating shelves but after googling around for “alcove shelves” we found this image - it was from a carpenter in Brighton who had made shelves out of mdf and then painted them - and they look like flowering shelves. I found a local carpenter and he basically copied the idea for us - and years later we still love our shelves, and several of our friends have copied them! We even copied the two lower angled shelves for our tv! The cost was also much better than buying ready made floating shelves or even Ikea offers. My top tip - find a local carpenter!

Having shelves either side of a flush fireplace will make the fireplace recessed which might look odd. Putting my neck on the line here but have you considered getting rid of the fireplace all together and replacing it with another focal point which is, in essence, what you are after? Some years back I visited a new friends house for the first time. I visited her again and again and then it struck me. In my minds eye she had a fireplace with her nicknacks artfully placed either side but in actual fact she didn’t. There was no fireplace. I was so struck by the optical illusion I vocalised it out loud. She said she didn’t like the flatness of her 1970’s house but didn’t want a fireplace. She deliberated over it for a while and then decided to instead build a stone ‘hearth’ running the full length of of the wall. It was many years ago and we have lost touch but I seem to remember shelves, ornaments and books etc. The seating was then arranged in such a way to support the illusion. There are many images of bookshelves, cabinets etc covering a wall on Houzz. The ones I find most effective are those that have low cupboards running the full width, with a wide central area with a picture, mirror or TV and shelves, perhaps with shelves above and or below. Either side of this focal point are more shelves broken up with vertical dividers running closer together. I hope I have conjured up something in your minds eye.

It would be more normals to plaster a wall than concrete it. . If it’s definitely concrete you may well end up pulling out the bricks too?

Lovely, cosy room. I don’t think you need to do much, unless you want a complete change. I would remove the wallpaper and just paint the wall the same as the rest of the room, although panelling would look amazing. I don’t think you need a rug as you already have carpet. Maybe some new cushions?