My friend calls Poland very often from London - I wish to make the referral to move over to ID Mobile but he uses a lot of minutes. The current plan available is 100 minutes for EU for £5.00 a month.

My question is can the auto-top top for add-ons be added to his account or are there limitations.

For example - Sim plan is £12/month. EU add-on is £5 for 100mins, can he buy more to add-on to that every month if he uses it up or set up an auto renewal.