Agree with the other comments. For me, looking for a 4 bed I would expect another downstairs space, it's more a 2/3 bed to me, small downstairs, with limited space for furniture configuration and somewhere I would grow out of quickly, so not a long term purchase if you're a young family.
I would remove the armchair completely to make the dining table and space more prominent.
Also I really dislike the pointy, dark architecture so think that will put some people off, lots of plants needed to soften it. The balcony is just wasted space, I can't imagine ever sitting there looking out.
I may also put a day and night blind in the kitchen, as the window makes it seem very overlooked.
Also yes to declutter the study, can you replace the desk with something smaller? Remove all the stacked up boxes.
I think it has niche appeal