Hi Craig,
Virgin credit cards are atually MBNA cards, and whilst they offer high credit limits and an interesting initial promotion, they don't always provide further deals.
The best way maybe to pay off the balance, then try each of your card lenders and ask them what promotional BT rates they can offer.
I did this recently, and MBNA didn't budge from the 34.9% + 5% BT (if I was crazy / desperate) to do this.
I went to Halifax, and they offered me a 0% for 6 months or 5.9/6.9 for lifetime + 3% of the BT.
I believe it is difficult to get more than one MBNA CC but not impossible, however before applying for any new cards, you need to make sure that you close down, or reduce the credit limit on your cards to reduce your available credit which could get you rejected.
Good luck with it.
Sparky.