Thank you for your reply. I have had to visit our local Virgin shop and they have swapped my SIM twice now and I now have to wait until Monday to see if this sim will work after migrating to my old number. Fingers crossed!
The second sim has migrated successfully but I did have to wait a long time for the problem to be resolved. My initial problem was that my sim would not connect to Virgin in my new phone. This will be ongoing for a while as my sim tray has jammed and will not let get access. Meanwhile I am using my old phone.