I'd agree with what everyone has said about lack of communal space. Based in Google street view you've done this conversion in the last couple of years and I doubt you will recoup the costs of it. It's a 5 bed house but looking at the virtual tour all I can see is a total lack of storage
Other people have suggested how to zone the downstairs space so I won't repeat their ideas. But definitely make a "dining area".
I assume your children are still quite young based on toys and decorations which means it works for you right now but you need to think about how it potential buyers can make it work for them and their kids who are unlikely to be the same ages as yours and will have different needs. .
If this was me I'd do the following in the bedrooms:
Switch the bedroom 1 from being a childs room to the master bedroom which presumably it was before the loft conversion. If you can't do that, take out the mismatched units from the room with the double bed so you can access it from both sides. Most people don't want to risk having their legs pressed against the radiator. Get rid of the brown Amazon boxes off the shelves. In the child's room get rid of some of those role play units, there's a cafe, a shop, washing machine, kitchen and an ice cream parlour. That plus all the soft toys and bench and toy box plus dolly things is just too much clutter.
Switch the office space to the loft and move a child into the room that is currently an office. if you can't get rid of the two additional monitors on the shelves and snake the wires in front of the shelving unit to behind it . Get rid of the plastic drawer unit too and see if the little pedestal unit will fit under the desk. If not get rid, it's making the room look much smaller and more cluttered
Loft space, get rid of all that marvel stuff and the shoe rack in front. Again it's screaming this house has no space in it and the mismatched furniture types just add to that feeling. The shelves with doors aren't full of booms so get rid of one and put all the books into a single shelf unit and arrange it centrally
Fox bedroom. Again get rid of the plastic drawers. Can you move the chest with the name on it to underneath the TV and then the unit twith the blue boxes o in front of the door to the eaves so it's next to the chest of drawers.
Tiger bedroom. Are those tiny desks used? Get rid of at least one if not both along with the plastic drawer unit. Move the unit with the name on to understand the TV and then the square pink drawer unit along the wall next to the bigger drawers. Not sure what the third low table thing is but do you need it? Get a small white bedside table next to the bed.
Shower room is fine but hide the potty!
Get all pictures retaken and a much better description.
Ultimately I don't think you'll reach the asking price but the upstairs space will flow better and feel less cramped