Every banks in UK can issue debit cards to their customs. But if you asked about what banks in HK would issue this for uk students? The popular ones that many HK students use are HSBC and EAB. But their HK branches cannot ISSUE debit card, they (their intentional bank department) only help you open the UK bank account and apply debit card by sending your application to UK branches for you.
1. Like the ATM card in HK: You can withdraw money from cash machine with VISA logo(No service charge).
2. Function like Octopus.
3.Function of Oyster card in London.
The bank must have sent you a PIN, use that PIN to withdraw cash, same like ATM in HK