I need help decorating a flat

Design details: I have recently moved into an unfurnished flat. I have bought the major furniture pieces. I am looking for someone to advise me on how to decorate the flat: paint walls, buy lamps/rugs/pillows, buy smaller pieces of furniture such side tables. I am would like to stay involved and pick the pieces myself but am looking for someone with an expert eye who could give me ideas/guidance.

Ideas for the visual style: We have a fairly modern flat. Please see photos of living/dining room, hallway and bedroom.

Extra notes: I am looking for someone in London who could come to the flat and see it in person. I am not sure how long it is meant to take so the budget is indicative.

If you could please send me photos of flats which you have decorated in the past, that would be most helpful.