Well yes you can check award seat availability online - you will need to log-in to the Virgin Atlantic Flying Club page first and then click on 'Spend Miles'.
If you don't have an account, let me know the dates and I can check for you.
What class are you flying? Upper? If so, it will be booked in G Class.
I take it that you have no status with Virgin, otherwise there are ways of having award seats made available
Thanks,
Richard