In the report we should show how we:

a) added acceptance tests covering the existing code, and any new code you write
b) added unit tests
c) refactored the existing code in order to achieve the above
d) wrote new code
e) anything else you did
f) how would you manage adding further features to this code in future


However it isn't clear on what to do about the new payment functionality required. 

To be honest - I would remove the old functionality as it was "requested by regulators"