DL-6066 enterPayeReference.scala

Checklist

[ ] I've made every effort to commit high quality, clean code and I have executed relevant static analyses to be sure
[ ] I've included appropriate tests with any code I've added (Unit, Integration, Acceptance etc.)
[ ] I've executed the acceptance test pack locally to ensure there are no functional regressions
[ ] I've added my code using logical, atomic commits, squashing as appropriate - including the JIRA issue number in the commit message
[ ] I've run a dependency check to ensure all dependencies are up to date