I haven't tried ordering anything through my affiliate link, I've only used the normal O2 link (www.o2.co.uk). Mainly because you can get free pay-as-you-go sim cards from the standard O2 shop at the moment but they cost £12.99 through the affiliate shop.
I don't really push O2 anymore because why should my visitors pay £12.99 when they can get the same product free by going directly to O2?