Since you said she's a very light user, she can get Be's Broadband for £14 per month with a 4GB usage limit.
www.bethere.co.uk
https://www.bethere.co.uk/belitehome....do;jsessionid=
I know it seems extreemly fast, but broadband at that price is very good.
I used the postcode
LS26 0RA to do my search.
http://www.samknows.com/broadband/ch....php?p=summary
You can click on LLU or Cable etc using her real postcode to do the search on that site, you can also enter her phone number to get a better result.
i hope this helps