I don't know the area at all, a quick look on Rightmove shows another house in your road sold last year for more than yours is on for which could suggest price isn't the issue..that had some interesting decor but it did have a more conventional garden.
Decorwise your house looks very appealing, it's clean and tidy, but clearly still a family home, I think maybe the garden is letting it down, you seem to have 3 separate sections, a paved area, decking and then lawn but I can't get a sense of it all together..is the lawn area at the bottom of the paved area, on a lower level?
The garden photos aren't the best, the metal frame of the gazebo feels a bit sad.. And also the garden does feel quite overlooked, although I'm not sure how much you can remedy that. Hopefully someone will have some better garden advice than me.