After the last cache, continue along the public footpath and it will come out onto the Leigh Road. Turn left and then as the road bends around to the right, take the turning on the left, which is signposted Powder Mills. Just before the turning, you'll have a chance to grab another geocache - Kent Oast Houses #14.
After a short walk along Powder Mills, you'll see a small bridge. While searching for the geocache, you'll see the housing development taking place behind you, which is called 1811, named after the year the old Gunpowder Mills were founded. More recently it was a site of a pharmaceutical company, which closed the site in 2010. Around 70 homes are being build here, so be interesting if people can post pictures of the changing site.