A wildlife trust will turn farmland into a haven for nature after supporters donated more than £250,000 to fund the purchase. The 26-acre site in Polhill, Sevenoaks has been bought by Kent Wildlife Trust after an appeal to the public to raise £195,000. The charity had until Saturday, June 1 to get together the money but the target has been smashed. The site, which is the size of 19 standard 11-a-side football pitches, had been previously managed as a commercial farm. It will now become a biodiverse chalk downland – a rare habitat which supports a wide variety of plants and animals and requires…