At the moment, the choices are largely either:   to limit the additional information to the 18 characters permitted by the direct entry system;    to separate the payment from the information and put in place a process to bring them back together at a later stage;    or to pay by cheque attached to the information source.
But to explain the realworld outcomes we also have to allow for the role of other influences, specifically structural change. A portion of the swing in the budget balance was of course due to the cyclical upswing. In our analytics, we were able to control this by holding the level of output constant at potential output.