Managed to get through to Customer Service and spoke to Zane. When I explained the circumstances about an elderly relative he arranged for an engineer to visit the same day and the phone line was working a few hours later.
There was apparently a problem with cables outside the house and the engineer identified and fixed the fault.
It was difficult to contact anyone at Virgin, but when I did manage to get through the situation was dealt with straight away.
Whilst i'm glad your issues seem to be resolved. I would like to double check to ensure everything is in order and up to date on the account, to make sure if the phone line ever went down again that there's not a similar issue to get the fault fixed. I am going to send a private message. Please look out for the purple envelope in the top right of your screen.