It the virgin box packing up. The technician came out to look at ours and changed it over, said once it starts doing it there's no repairing it.
I used to keep the two boxes on top of each other too which may have been causing them to overheat and cause the issue. Advised to keep the new one separate.
Definitely contact the virgin media team through here. The technician said it was the quickest way to get hold of someone.
Good luck!