Sort code passing even though it doesn't exist

[branks]

Sort code : 04-21-13
If you go here - http://www.fasterpayments.org.uk/consumers/sort-code-checker - you can see that the sort code is not valid and does not exist. However it seems to pass all checks with this library

[franciscocardoso]

Hi @branks

From what I can see the sort-code-checker site is only saying No matching sort code found!. Maybe thats because that sort code was not emitted.

Please notice that this module only validates that customer codes and account numbers are compatible.

[branks]

So building on that, I have found that any account number that uses the sort code of 12-34-56 is a valid combination, is this correct? This seems to make this library quite unusable for validation as 123456 is quite a common dummy sort code