You should pull up and remove weeds by hand as and when they appear. If it is a regular problem, you might need to reseal the paving. In extreme cases, the sub layer itself may need to be re-laid. You can use weed killer, however some paving can be discoloured by stronger weed killers.
Isle Of Harris
Harris is the southerly and more hilly part of Lewis as well as Harris, the largest island in the Outer Hebrides, Scotland. Although not an island itself, Harris is typically referred to as the Isle of Harris, which is the former postal county and the present article town for Royal Mail postcodes beginning HS3 or HS5; see HS postcode area. St Kilda, an unoccupied tiny island chain, located 40 miles (64 kilometres) west-northwest of North Uist is thought about part of the civil parish of Harris. The same holds true for the remote unoccupied rock island Rockall, which is 230 miles (370 km) west of North Uist. According to the 2011 Census, there are 1,212 Gaelic speakers (60%) in Harris.