It clearly states in the standards document that you must hold or be eligible for a UK RT licence BEFORE taking the UK JAA CPL skills test. A commercial pilot really has no excuse for not knowing this.
A commercial pilot would have also searched the CAA website and found :
RT Examiners: List of Authorised Flight Radiotelephony Operators Licence Examiners | Publications | CAA
Again no excuse for not researching.
Your lucky they even recognised your test, and didn't make you re-do it.
Given the skills you've shown so far - I know which route I would have taken....