Give u an example. Last year I've lost my Lloyds card, went to branch and asked what should I do. Woman said that I should call to given number and provide plenty of details about myself and my bank account including whether it is joint or sole account, what is my overdraft limit and so on. U may be sure it's not an afternoon walk to bypass verification process.
Ring3 If you want to find out what exact info you need just call the bank and ask for the info. Tell then you want open an account and want to get some info reg security. What security questions they will ask you etc. just need to sound legit when you ask.
With Barclays Bank: MMN and DOB, billing address, recent transaction, overdraft limit(or credit limit), what services you have got on your account. Being honest its quite hard to do but it is doable
Best thing for you is to buy UK cc with a valid phone number. Process takes some time but what you have to do is call the owner (good English is necessary, spoof card) you call the person and say you from the bank and got some offers to them well any thing that will bring their attention will work. You ask probing questions to match the requirements from the Bank they got. Ask 3 questions and you got the info. Few days after call them again reconfirming the benefits or something else you offered them and ask another 3 questions. if you cant get all info by those 2 phone call make another one. When you got all the info you call the bank change the billing address and send new card with pin to you. Then you have to call the owner of the card an tell them that you are issuing a new card for them and the old one will not be valid.
As long as you sound professional got a good background (call centre noise is necessary) then people give back their info. 6out of 10 people give all the info over the phone so the score will be easy.