...if I only require 5 hours and no test, then IMC it is.
You will need to pass the IMC Rating Flight Test. From LASORS:
JAR-FCL professional aeroplane licences do not have inbuilt IMC privileges.
The holder of a JAR-FCL professional aeroplane licence who wish to obtain an IMC Rating must complete the requirements specified below:
1. JAR-FCL CPL(A) holder without an IR(A)
To gain an IMC rating a JAR-CPL(A) holder will be required to complete the following:-
i. 5 hours of applied dual instrument instruction in accordance with the IMC Rating syllabus and;
ii. pass an initial IMC Rating Flight Test.