I have a sort code (and an account number) for Barclays 20 32 00 how can I find out the IBAN and bank details to make a payment to an account under this sort
I'm not sure why you need it. Are you paying a bill/transferring money online?
For my online accounts I just need the sort code and account number to transfer money to someone..
Who is asking you to provide this info?
Have you asked the recipient?
I am making a payment to this account from Europe and need an iban and bank address for this transaction I know it is Barclays but not the branch and so I dont know how to make up the iban from the account number and sort code?
IBAN's are individual for each account, so you will not be able to look this information up yourself. The account holder can obtain the details from their branch, although it's probably already on their statement if they get a chance to look.