That's not how it works, SE doesn't give the items for free to 02 customers. Essentially, being being a part of 02 priority allows you to gain exclusives for free (not just xiv stuff, but other discounts, vouchers, promos, and competitions), so essentially that £10 is still being paid, but is subsidized by 02.
The thing is, the mentality of the real world allows for exclusive free stuff that would otherwise be paid for because it makes the service more appealing, it is only on XIV where this fact is different (not saying the entire campaign isn't poorly managed, just saying that the 02 campaign itself has no problems).
