Distance from the exchange has no bearing on FTTP availability, and although a 12 year old property could have FTTP , back then the developer had to request and contribute towards Openreach costs if they wanted FTTP providing , if they didn’t request FTTP , they were provided with a copper pair service, presumably the developer/builder of your property either didn’t want to make a contribution towards FTTP or decided it FTTP wasn't necessary .
FTTP , comes from certain ‘headend’ exchanges, not necessarily the exchange you are closest to, so although you may be really close to a local exchange it may not be a ‘headend’ , that could be in an exchange upto 40Km’s away , even if it is a headend exchange, it’s not really an advantage being 800m from it .
At 12 years old , the Openreach infrastructure provided for copper pair service ( footway joint boxes , ducts etc ) should make the eventual provision of FTTP fairly easy , but OR cannot upgrade every area simultaneously, you can check with OR if there is any current plan for your area
