If your other router is just a router and not a gateway (router and modem combo) then yes it could replace it. The WR841N is a low end router good for someone who has low speeds (less than 100 as 100 is the MAX speed)) and only needs one WIFI channel (2.4GHz) as this is not a dual band router. We do not have Plusnet here in the US. You may want to post on https://community.tp-link.com/en/home/forum/32 (note 'en' vs 'us' in link) as it is the English non-US site and others may have a better idea of your equipment.