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.
Colwyn Bay
Colwyn Bay is a town, community and seashore holiday resort within Conwy County Borough on the north coast of Wales overlooking the Irish Sea. Eight neighbouring residential areas are integrated within its postal area. Started as its very own separate parish in 1844 with just a small collection of properties and farms where the community of Old Colwyn appears today, Colwyn Bay has expanded to become the second-largest community and business centre within the north of Wales plus the 16th biggest in the whole of Wales with the urban statistical location possessing a populace of 28,992 at the 2001 census.