Financial proof has to come from either a bank statement, saving accounts passbooks and the cashier order or bankers draft is for the payment of the visa fee.
It takes about an hour to open a Hong Kong bank account. You need your passport and proof of address. It's trivial, just get on with it!
If you still have bank accounts in the UK, First Direct or HSBC (the old Midlands) would be the most useful. But there are also branches of Barclays in Hong Kong (albeit only for rich people!).