Hi, I'm in Spain at the moment, and just wanted to post this message about topping up.
Instead of ringing customer services, I text CR and then the amount to top up, followed by the last four digits of my card to 789000. For instance to top-up £10, it would be CR 10 1234 and send that to 789000. It took a while to go through, but if you have to top up in one month to get freebies the following month; it's worth it.
In Reply:- If your card details are already registered with Virgin mobile, you only need the last four digits to top up. You used to need the three security numbers on the back as well, but now they've simplified it to made it quicker. This works both on the 789 number in the UK, and with the 789000 number in Spain.