So... what was the manufacturer name and model of her DSL modem?
smartAX MT882.
A quick search later pulled up the fact it was indeed a modem and a router, as well as some interesting links:
The user manual for the Huawei SmartAX MT882 can be downloaded from driverguide.com [driverid=503416]
There was a Talk Talk specific page at kitz.co.uk which had the following snippets:
You are best connecting this router using ethernet and following the instructions on the setup sheet for an Apple Mac computer.
Ethernet
If you use Ethernet you wont need to install any software on your PC. Simply:-
~ Connect the router to your computers Network card using the supplied network cable
~ Browse to http://192.168.1.1
~ Log in using the default settings username = admin and password = admin
~ From the left hand menu select Basic
~ Select WAN settings
~ Click on the pencil icon on the top right hand side
~ Set your username and password as given in your TalkTalk welcome letter
which should be in the format of yourphoneno@talktalk.net
~ Click Submit
~ Click Save all
~ Click OK
and a discussion on the broadbandbuyer.co.uk forums about connecting to Talk Talk using that Modem/Router.