We have upgraded our flights with virgin to PE. When I rang to sort our seats etc, they informed me I was entitled to free flights (to anywhere) between 1st September and 12th December. Apparently, if you travel PE with virgin between 1st June and 1st September (check those dates, I'm not 100%), you get a free economy flight (you just pay tax). Alternatively, if you are a member of virgins flying club, you can buy one PE flight and get another one free. Virgin have all the details on their website, but its down at the moment.
I thought this may be useful for someone.
I thought this may be useful for someone.