Hi guys Ive just got a new pay and go sim card through for my iPhone from Ebay (12 months free Wifi) and I want to change to my old number from my pay go sim I used on my old phone (using https://www.o2.co.uk/apps/help/help?qid=29&q1=22) but am not sure when to do it. Should I activate my sim with my iPhone and everything through itunes first? (basically getting everything set up), or should I change my number before even putting the sim in the phone by just sending off the sim details on that form? Also, when the form asks me the last time I topped up, is that for my old sim card or my new one? (as I haven't topped up my new one yet). Many thanks.