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.
Porthmadog
Porthmadog known in your area as "Port", is a tiny Welsh coastal town and previous community, now in the community of Penrhyndeudraeth in the Eifionydd area of Gwynedd. It has been so led to formally given that 1974. Before 1972 in the administrative county of Caernarfonshire, it lies 5 miles (8 kilometres) eastern of Criccieth, 11 miles (18 kilometres) south-west of Blaenau Ffestiniog, 25 miles (40 km) north of Dolgellau as well as 20 miles (32 kilometres) south of Caernarfon. It had a population of 4,185 (2011 census). It established in the 19th century as a port exporting slate to England as well as elsewhere, yet given that the decrease of the sector it has come to be a mall and also tourist location. It has easy access to Snowdonia National Park and is the terminus of the Ffestiniog Railway. The 1987 National Eisteddfod was held in Porthmadog. It includes the nearby villages of Borth-y-Gest, Morfa Bychan and also Tremadog.