I have been using Virgin PAYG for ages and thought it was high time I switched to a contract as my top-up bills are quite high each month. I applied online, my order was accepted and then I received an email to say they'd hit a snag and that the credit reference agency had linked my details 'to a couple of different addresses' and they wanted me to phone to talk it through. I haven't called them yet as I'm terrified that something untoward is going on.

If anyone has any idea what this credit check 'snag' is all about I'd love to hear from you.

This is fairly standard. Credit score info is not just a matter of yes or no, they may need to clarify something with you or simply ask for proof of your current address before they sign you up. This is to make sure that you are who you say you are before they give you a phone or offer credit to you.
But if they are not a company you are happy with or feel that you don't know enough about them then you can always walk away

Cerbius