It is a lovely house but as PPs have said, the photos are confusing, and the garden is too small.
I think the house is almost "too big". Most people don't need that much space, so many bedrooms, even a large family. You need to "tell" them what to do with the luxury of so much space and sell them the lifestyle. One of the advantages of having a big house is being able to have dedicated rooms like a home cinema, home office, playroom, laundry room, formal dining room, music room, games room, library, ensuite bathrooms. You don't need to have multipurpose rooms. Yet you seem to have a desk in the kitchen, another desk in the family room and no home office. You don't have an eat in kitchen, you have a breakfast room but then another dining room with a tiny table which doesn't look any different from the breakfast room. If you are going to have a formal dining room, make it look grand with a big table for dinner parties, otherwise you are just doubling up. Or use it for something else. Show people what they can do with all the extra space.
I would rethink the rooms. Maybe make the breakfast room look more like a formal dining room, then turn the dining room in to a family room and move the TV there. Then turn the basement family room into a library/office/music room. I know it's got to work for you living there too but at the moment it feels like you have 2 dining rooms and 2 sitting rooms, and I only need one of each... Inspire people as to what they could do with all that extra space.
I would also get the agent to clearly mark the self contained annexe on the plan by greying it out or something and renaming it as a granny/guest/au pair annexe. I would consider whether you need a guest room and the annexe. More people will need a guest room than a granny/au pair annexe but then they don't need a guest room in the main house. It might be worth considering repurposing your guest room as a study, if you have one.
The lack of outside space is a problem for such a large home? Where is the off street parking mentioned in the details? Is it attached to the garden? If it is, it might help to have a plan of the garden, as it would give people the option of using it as garden space rather than parking.
The courtyard seating area looks cramped and uncomfortable with tiny stools, a small table and wooden benches. If you added cushions, maybe added some proper chairs or at least spaced out the stools, it might help make it look more comfortable and show there is room for everyone to sit there. You've got a granny annexe and 5 bedrooms but it doesn't look like you could fit the entire family around that table.
I would spend some money of redesigning the front garden. Buy some large trees and shrubs in pots to create a hedge to make it totally private so people feel comfortable using the space. I would add a seating area with sofas or a swing chair so buyers get the idea that they could actually use the front garden as in the same way they use a back garden.