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.
Cockburnspath
Cockburnspath (population 411) is a town in the Scottish Borders location of Scotland. It lies near the North Sea coast between Berwick-upon-Tweed and Edinburgh. It goes to the eastern extremity of the Southern Upland Means a long-distance path from the west to eastern shore of Scotland. It is additionally the termini of the Sir Walter Scott Way and the Berwickshire Coastal Path. At the neighboring town of Cove, there is a tiny fishing harbour.