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.
Kendal
Kendal, anciently known as Kirkby in Kendal or even Kirkby Kendal, is a marketplace town and civil parish inside the South Lakeland District of Cumbria, England. Traditionally in Westmorland, it's 22 miles (35 km) north of Lancaster and 50 miles (80 km) south of Carlisle, about the River Kent, and has now an overall total resident population of 28,586, so that it is the third largest settlement in Cumbria, behind Carlisle and Barrow in Furness.