Have you set this up as the router modem for now broadband or have you set up up as a wifi access point that connects to the now broadband box?
it goes against what I've been reading here, people saying to use MPOA option 61. There is no MPOA option in any of the tplink router modems I've seen.
You could read the whole of this thread from page 1, compare the conflicting reports, and then go and learn more than you ever wanted to know about router protocols, and set something up for yourself that might or might not work.
Or you could get a techie friend to do that.
Or you could just use the router that NowTV Broadband supply with their service, which will arrive preconfigured and all ready to go.
Issues with this router are:-
It has only two Ethernet ports. If this is a limitation for you, you can increase this to four or eight with an Ethernet switch from Curry’s or Amazon, £15-30; no configuration needed, and although it’s called a switch, there is nothing the use has to switch; it’s the Ethernet equivalent of a multi-way mains adaptor, but for Ethernet signals.
The WiFi is not all that strong. Best to first find out if this is a problem for you, and in what way, as there are various ways to overcome this.
Are you a subscriber to NowTV Broadband?