TalkTalk fibre (TT on FTTC) 2760n settings:

In router go to;

Network > wan> DSL
edit or add

then;

Enable ticked

Name PVC1
Description, whatever you want or blank

Profile Type VDSL2

Protocol setting:
IP Version IPv4
Protocol DHCP

MTU 1500

PPPoE Pass-through Enable unticked

VLAN Encapsulation ticked

VLAN ID 101

Priority(802.1p) 0

IPv4 Setting:
connection detection ticked
connection detection mode auto
always on ticked

APPLY those settings

Network > wan > DSL mode
set to auto
APPLY settings

Maybe reboot to start fresh, but your TT fibre should now be working on your 2760n