Hi A_Ash,
Welcome to the Community Forum and thanks for your post. It's great to see new faces here.
I've got some good news--go ahead and get your old rotary phone because it will work on your Virgin Media line.
I do need to make sure that you are aware that if you need to go through any IVR system--for example, you need to call in to us here at Virgin Media--your rotary phone won't work. It also won't work with other call features on your line like voicemail. But if you have a tone dial phone spare or connected to a different phone socket there's no worries.
Please let me know if you have any further questions.
Thanks,
Terri