Four Very Spacious Bedrooms
Beautiful Private Gardens
Outside is just amazing
Maybe prospective buyers are reading the description and wondering where the above things are, it really doesn't match with the pictures shown.
Personally I'd say within in the boundary of your property there's nothing amazing or beautiful about the outside space, and although you bought up your DC there for a time some may see the back garden as a space that's not suitable as it is for young children to safely play in.
Internal cosmetic decore shouldn't really be a problem, clean, tidy and in reasonable condition is livable as most change decore anyway.
People are wise to how they spend their money and when buying a property its a big expense and not a matter of just paying out for asking/buying price and that's it, job done with, there's solicitor fees, stamp duty and whatever charges are thrown up along the way.
So anyone moving in on the top end of their budget wouldn't necessarily want the expense of having to payout to renovate, especially the back garden immediately.