i stand to be corrected, but i believe its 800 homes "impacted", not destroyed. the site of the second runway largely replaces warehouses and office buildings. the impact count is a couple of orders of magnitude lower than those in London.
Directly from the report :
"
All of the three schemes would result in a loss of homes in the local community due
to the land take required to construct the expanded airport, as set out in the Place
module. These impacts would be largest for the Heathrow Airport Northwest
Runway scheme, which would require the loss of 783 homes, including the entire
community of Longford and much of Harmondsworth. The loss of housing required
for the other two schemes would be smaller, though still significant, with 242
houses estimated to be lost as a result of the Heathrow Airport Extended Northern
Runway scheme’s land-take and 167 lost due to the Gatwick Airport Second
Runway scheme. "