Is it Virgin Media cable phone? Or a normal BT-type landline?
If it is cable then the only broadband is Virgin Media, unless she gets a BT-type line as well.
If it is a BT-type line already then it is technically possible to get most ISPs in the country. But Virgin Terms & Conditions may say no, on commercial grounds. You need to check them.
If it is a BT-type line, what exchange is it? We can recommend the best for her.