Re: Gatwick is a big place
"The airport perimeter is something like 10km long."
And a couple of lidar scanners can cover it all.
This isn't exactly a "new" problem and the longer it goes on without any evidence of said drone, the more likely it is that there never was a drone to shoot down in the first place.
https://www.psychologytoday.com/gb/blog/wicked-deeds/201507/moral-panic-who-benefits-public-fear