Hello, In first time, excuse my english, we are three spanish guys and will be stay some days in London next week. We will buy at least 6 iphones, and we don't know if we can get the phones or we will have problems to get them. Can we pay with cash in an O2 or carphonewarehouse stores? We only have 4 visa electron debit cards, can we use it for pay iphones in this stores? Are there any limits per person/debit card? Some conditions that we would know before try to buy iphones in this stores? We need all the tips you can get us. Regards.