Caller ID Not Working for International Numbers

Dear Virgin Forum Team,

I switched to Virgin Media towards the end of last year and previously we were with Sky.

Since moving over, we have had ongoing issues with our landline that the engineers or customer service have been unable to resolve. 

Since my father is blind, he relies on 1471 to tell him whose calls he has missed throughout the day. He has a lot of family calling from America, Australia and Bangladesh. However since switching over to Virgin, whenever his family members call from abroad, it is never picked up by the phone and shows up as 'No Caller ID' which is very frustrating for him. When I leave a missed a call from my own mobile phone (UK number), my phone number was registered by 1471 and seems to be working then.

We never had this problem when we were with Sky. We had an engineer visit the property once before who said there was nothing wrong with the landline and my ongoing discussions with customer service led to nowhere unfortunately. I decide to just leave it but my father has been getting more upset at losing this feature he once had so here I am trying to sort it again. We are likely to switch back to Sky at the end of our contract should this continue. 

I have seen a number of posts on these forums who seem to have been successfully helped by the forum team and I am hoping for the same. 

Please let me know if there is anything that can be done about this.

Many thanks

Obi